Allocating resources based on some theoretical rest breaks that may or may not happen has the potential to either screw over the players or make things far too easy for them.
Not allocating resources has a very similar effect.
For example, there are many older adventures that kinda fall apart if you have reinforcements come from anywhere they might come... or don't. Too hard, too easy. Sometimes murderously or boringly so.
Having some idea of what's 'in the vicinity' (aka, what could show up for a single combat, before the PCs have a time to catch their breath and pull out their healing salves) is helpful. No matter the rest of the dressing or prejudices associated with the exercise that leads you there.
I do think Firelance is onto something that there's a strange... funk... around the word "encounter".
...
Now, let's instead imagine that wizards get mana, and fighters get fatigue. Let's say a wizard can use mana to power any spell they've prepared that day, and fighters can spend fatigue to perform exploits that they pick up when they level.
Is it a problem if both mana and fatigue are restored by taking a rest?
How about if a fighter with no fatigue can burn hp in place of fatigue?
What if wizards have a small pool of mana - only enough to do one of their biggest spells, but they recover some mana every round?
There are _many_ ways to turn the game away from "You have 3 abilities that have 5 minute cooldowns" - which I think we've safely identified as a gameplay behavior that sufficient people are not interested in, while still avoiding "There is a hundredfold difference in capability between a rested party and one that is not, so the PCs will hoard and manage their daily resources to trivially obliterate what should be interesting combats, drag what could be cakewalks, and pervert the entire concept of resting to not match a sensible plot in any way."
Along the way, we can even fix the whole magic / martial disparity, and not just in a hypothetical "Well, if the day is 100 rounds long, the fighter really rocks for the last 80!"