The problem with exhaustion is that unlike other status effects which baring very specific circumstances/poisons, usually don’t last too long and don’t get worse than it already is. But exhaustion can’t be healed out without greater restoration, and without that you only lose one level of exhaustion per long rest. And if you have more than one level that’s multiple days you’ll need to be laid up, because you can only take one long rest per 24-hour. So can’t have three long rests in one day.

Exhaustion is debilitating because it’s so hard to remove, which is why the Berserker Barbarian is one of the worse subclasses one 5e, because of how easy it is to accumulate exhaustion.