Some have fun in quick games, short burst of fun. Others want to blow through the game. You have the mechanics junkies, who analyze and want to complete everything single thing. Why others want to get immersed in the world, taking it slowly.
All need different resting mechanics to satisfy everyone.
I personally liked the BG2 way. Can't rest in some areas (in cities the guards tell you to go to an Inn, but there were ways to go around that...). In the wild there is a chance for a random encounter scripted to that particular area - I think it was both quick and immersive.
Also I would think that different resting mechanics could be very easily modded in.