There's a line drawn for player convenience over realism, even in an RPG.
But I'm aware that many people do enjoy that effect. Me? It mostly drove me nuts in Kingmaker.
"I want to walk to that town' *EXHAUSTED*
'Ok, I have one more fight in this cave' *No! Go camp! NOW!*
'Man, I'm doing good in this fight" *Now you're exhausted IN the fight!*
Again; I'm not against it being an option for players to pick and choose, but I know I would not enjoy it. I like resting to replenish my HP and spells. Or because I want to give my party a bonus of some kind. NOT because the game forces me to rest based on its internal clock.
I mean 1 level in exhaustion only gives you disadvantage on ability checks (out of combat stuff such as persuasion, perception, thieves toolts etc.) so it's really not that bad. The bigger problem is spell slot management, which if you're for removing as well you might as well play a cooldown based game instead
