These far more accurately model a Mr. Magoo type character. He isn't walking on that girder while blind due to a high dex. He's just getting very lucky.
A Halfling with the Lucky feat is a sufficient explanation for an NPC, (though the combination still isn't an Attribute).
A player is going to want to pick a class.
The point isn't accuracy, or total fidelity....the point is allowing players to try different ideas while still being effective. I'm a powergamer by inclination, yet I will happily make a suboptimal choice if it fits "my character".
but who rolls stats that way, in 5E, in 2020?
3 out of the 4 games I am involved in have rolled stats. I know 2 more ongoing games that also use rolled stats.
Your preference is subjective and arbitrary, and should not be presumed to be universal.
The above of course also applies to
my preference, to everyone's preference, really.
Sherlock Holmes isn't crazy, either. He's not going to insist that gunpowder works when it doesn't.
We don't really know that at all, being that no such short story
exists. All, serialized characters eventually wind up as experts at everything the plot requires.
Remember, the
prompt was a player approaches you asking to play Crazy Sherlock...and how do you respond...do you tell the player they must play Ruperick the monkey boy?
You need to RP INT 5 as a full array of being bad at INT-based tasks, not just "cute insanity" when its convenient/funny, if you're going that way
So your answer is
indeed one
must play Ruperick the monkey boy.
The point of the extreme 5 WIS/Must play a serial killer example is to illustrate that any DM prescription of how a player
should role play their character can result in them reacting just as you reacted, Ruin.
Many games, (perhaps most games), are ran at what I brand as:
Solve for "X" RPG Games.
The "X" variable the player is trying to determine, is what the DM will allow to work.
Some games are ran with the intention to invert that paradigm, the DM is the one that finds solutions for what the player wants to do.
Either style works, because D&D is like sex, a good intentioned, mediocre session with nice people, is still rather satisfying, even if it wasn't exactly the way you wanted it to be.