Encumbrance is a limitation. Limitations by itself invite creativity and are necessary.
Caveat: they
can invite creativity, and
can be necessary. But they also
can be stifling, and
can be not only unnecessary but actively harmful. Consider the Comics Code Authority and the Motion Picture Production Code/"Hays Code". That was a set of limitations on what stories people were allowed to tell. By your unqualified standard, that necessarily means stories written under it were more creative than ones not written under it, and that we
needed these limitations in order to have films worth watching. I think--I hope!--you agree that this is not true.
Hence, we must have
more than just the fact that it is a limitation. Some limitations absolutely do breed creativity; a classic example from video game design is
Silent Hill, with its use of fog to obscure the significant technical limitations of the PlayStation, allowing spaces to
seem bigger than they were. Instead of a roadblock that would have derailed the game (the player being able to
see that the game's world is in fact quite small and can't be rendered fully), they were able to leverage that limitation into a profoundly creepy atmosphere by
intentionally taking away the player's ability to see things from a distance.
Just declaring "it's a limitation!" is not enough. You must explain why it is a good limitation, a limitation which invites a creative solution on someone's part, rather than a bad limitation, like the Hays Code/CCA, which literally just prevented people from telling anything but dull, flat, milquetoast stories. "Limitations by themselves" are not a good thing (though they may not be strictly a bad thing either.)
In the special case the limitation of how much a character can carry gives the game strategic depth, invites dilemmas and problems to solve and makes the game feel more realistic.
Again, realism alone is not particularly productive. We don't track post-traumatic stress disorder for adventurers who are near-constantly in grave mortal peril. That would be
significantly more realistic than the cartoonishly badass, inviolable heroes we tend to focus on--indeed,
dropping that is one of the ways literal actual superhero stories have tried to become more realistic!--and yet there is essentially no effort and even less appetite for such things. Hence, realism alone is not the value--it must contribute to something
else.
And the assertion that it "gives the game strategic depth, invites dilemmas and problems to solve"
is the issue. I'm saying it
doesn't do that. It just adds tedium that must be worked through before one can get back to ACTUALLY caring about strategy and tactics and interesting dilemmas to resolve. What is the strategic depth of "oops, you're now carrying 1 pound too many, now you suck at everything, better drop something!"? There
isn't any. And in the vast majority of cases,
Without encumberance, the rules for eating and drinking, the tracking of resources like Torches, Rations, Arrows ... you remove the strategic game aspect of exploration.
Not at all. There are many ways to have strategic exploration in games which
don't narrowly track encumbrance and simply mete out annoying penalties for failure to comply.
The interaction of encumbrance rules with the rest of the world creates the exploration game itself. With that rule, there is no exploration game. It would devolve to just "I look for that thing in area x until I find it or until random encounters kill my group".
There ARE no such interactions! That's my point! It's literally just "are you above the line? Y/N." If you are, you get annoying penalties. If you aren't,
nothing changes. That's not a dilemma! It's not even going to induce difficult choices! You would always either just prevent it happening in the first place (which is what the vast majority of players do), or you would shed whatever item you can
calculate as being the least essential to your future success/least important for avoiding future problems.
Now, without encumbrance, they just go and search every hex field until the find clues.
Not at all! Even if there isn't encumbrance, they may only have X units of food, perhaps because of limited
funding. (It's not like they can just carry an infinite quantity simply because you don't track encumbrance!) Or maybe they choose not to carry food at all, or are not able to, and want (or have) to hunt for it themselves, which
actually does create decision-points (do we stock up on food as we go, hoping to live off the land? Or do we get lots of food
now, expending other resources, but saving
time later?) Other aspects of kit and equipment can similarly limit what is possible or practical without caring about encumbrance: you can only wield a few weapons, you can only wear a single piece of armor/clothing at a time, you can only manage a certain number of pack animals, etc., etc. And all of those things can actually reward better play, not exclusively punishing poor play (though they may also punish! Depends on how the rules are written.)
They will have some random encounters like hazards, monsters, the rivals, other nocs, other ruins or cool locations, that will give clues and so on ... and unless they TPK by one of those encounters, they just heal, long rest and continue until they find the temple.
These other things bring up a similar thing as the above. Bringing infinitely many tools and supplies is
not possible even in a game that doesn't track encumbrance. Further, all that stuff about
long resting? Completely unrelated to encumbrance. You're invoking completely separate rules here--long rests work as they work, unrelated to encumbrance unless you
house rule a connection.
Now with encumbrance and ressource tracking, how will that adventure turn out?
First of all, they have to plan the expedition.
What on earth gave you the idea that not tracking encumbrance meant you don't have to plan at all? Now you're talking contradictions. First you treat them as though they infinitely prepare for all possible things. Now you're treating them as not doing any preparation at all! You can't have it both ways.
Because of encumberance and resource management, the game got more depth, more realism, more decision points, a heightened difficulty. It improved the same scenario tenfold.
Again, no, it doesn't. Most of that depth either comes from completely unrelated rules (like long resting, which has
genuinely nothing to do with encumbrance!), or from things that are still true regardless of whether encumbrance is carefully tracked or not. Tools, supplies, preparation, training, and helpers/assistance
cost money, and even if you don't track encumbrance, you certainly should be tracking money--and players ARE rewarded for spending their money wisely rather than foolishly. There is no equivalent of "I scrimped and saved and bought myself a +2 khopesh of nasnas slaying" when it comes to encumbrance--saving 10 weight on one adventure and 20 weight on another adventure doesn't give you 30 extra weight to play with in an adventure that comes after them.
There are no
decision points because of the encumbrance. There are
calculations because of it. What can you calculate is most efficient? That's not a decision. You do whatever is mathematically superior. It's literally what numerical encumbrance tracking is about. Now, I don't blame you for conflating calculations with decisions--this is an error a lot of people, and especially a lot of designers, frequently make. But it really is an error. Calculations involve no value-judgment. They're simply crunching numbers and picking the optimum. There is
exactly as much decision-making involved in "keep your weight below N flibberweights" as there is in "take Great Weapon Master at level 4."
What is the advantage here? Realism alone does not justify annoying rules, because there are LOTS of annoying rules that could add tons of realism but which are actively avoided and clearly unwanted by most players. Limitations alone do not justify annoying rules, because limitation
alone does nothing to foster creativity and can quite easily stifle it. No
decisions come from this, only
calculations--literally, it's all about calculating the weight you can hold, ranking what you can least afford to part with, and dropping everything after the point where you cross your calculated limit. And difficulty for its own sake is literally what I'm calling this--annoyances with no benefit! "Solving problems" is only valuable if the problems are interesting to solve--that's why we have so many jokes out there about the "word problems" kids had to solve in school and how pointless and annoying they were.
No, you don't have to play everything out in minutiae. But for example latest at a long rest I tell my players to remove a days worth of food / rations / water from their inventory.
Is that strategic depth? Is that actually a "problem" to solve, a "dilemma" to wrestle with? Or is it, as I have asserted,
just bookkeeping to avoid annoyances?