Rest every 6 turns, where is the interesting choice?

In B/X, PCs have to take a rest of 1 turn every 6 turn or suffering a -1 to save and attack rolls due to exhaustion. Other systems like Cairn, give you a "fatigue" slot in your inventory and there must be many others. I think these penalties are nice, you want to consider ways to mitigate them.

My problem is, basically you always will want to rest.

Why would you want to press? To push one turn later the 1 in 6 encounter die? It seems very weak to me. There migh be case where spells are active and you don't want to waste turns, but it's very specific and feels clunky.

Rest sounds nice, it give tempo to the dwelve, could bring a bit reflection on the group, like a fire camp at night but I can't think of any situation where the PC would not rest.