It depends on how they're implemented, but some timers make sense.
Suppose you come across a wounded person lying on the ground, clearly on the verge of dying, and they ask for a healing potion. Quest received. Then you move on to find that healing potion, travel around the world a few times, and 40 years later you happen to come back on that same road and lo and behold, the wounded person is still there, waiting patiently for that potion. That doesn't really work, does it?
Same with the imminent gobbo attack on the druid grove. You know that it's about to happen, so you get going on the long journey from the gobbo camp back to the grove. But the weather is hard and the path is dangerous. Getting lost is a constant worry. Therefore it takes about 14 long rests before you make it. Oh look, the imminent attack that is starting right now hasn't happened yet. It seems the party made it just in the nick of time.
Same with the airship in the prologue that is totally going to be destroyed and you have to hurry and connect those wires to teleport away now. Right freaking now!! Or we're all going to die!! Any minute now... Certain death incoming. We're totally out of time, must hurry... Yeah, not really all that convincing, is it? But if something actually happened if you delayed enough then that would change the dynamic.
