Why exactly do we need to force the number of rests? What's preventing characters to do nothing for 24 hours? If the number of rests were connected to the story then sure, but a lot of people hate time limits. It's a single player role-playing game without "ironman" mode, so just roleplay according to your standards.
Ah, but it is not a single player role-playing game. One of the significant parts about Larian games is that they have strong multiplayer support, a trend which BG3 continues and even builds on.
So what happens when, in multiplayer, one player chooses a wizard and one player chooses a fighter/barbarian? The allowance for infinite rests means that the wizard can just have so much more to do every fight. It's a big unfair to the person playing fighter, yes?
Sure, but you could just discuss with your friends whether you should rest or not - it is not like you'll be playing with strangers.