I think they created the "food buffs" and "Inn buffs" in POE to give the players a reason to rest because many builds do not need it anymore.
When you design a dungeon you could make it more challenging by limiting the rest so they have to manage their limited spells/resources, but my personal opinion is that you can allow semi-unlimited rests if you plan your encounters considering a fully-prepared party at all times (I.e-> The original PF:k campaign). I´ll add the possibility of random attacks in the camp, of course.
But usually, you do not use things like "automatic healing" and "spell cooldown recovery" between combats in D&D so you can start all the combats fully healed and rested. That´s very MMORPG-y.
