I use those encounters to serve as a exploration encounter... They serve to inform or reeal aspects of the environment.There has been a lot of criticism over a lot of threads about easy encounters being a waste of time. Why should a DM bother with a 7th level party having a fight with a single CR 5 monster?
Or [CR 3 + CR 2]?
Or [CR 2 + (6 * CR 1/4]?
Or [12 * CR 1/4]?
After all, the PCs should be able to kill these enemies without using many, if any, limited resoures. If they can win without losing many hps or using any non-cantrip spells - why have the encounter?
The answer, generally, is that the challenge in the combat is not whether the heroes can survive the battle, but whether they can stop the enemy before something else happens. The threats are not about threats to the PCs, but threats to things the PCs care about. Or, alternatively if they can solve a mystery before the combat ends - or navigate a non-combat challenge during the combat.
Perhaps they need to stop a rampaging fire elemental before it can burn down the town. Perhaps they're hunting an illusionist who is guarded by an ogre - and the goal is to capture the illusionist before he escapes. 12 Goblins attacking a caravan is no threat to the PCs, but what if the PCs need to make sure the caravan passengers all survive?
What do the PCs do when 6 Drow led by a Priest (also drow, but using the Priest structure) burst into the tavern from the basement and drop darkness.... what do they want? Why are they there? Are they trying to do something and then escape? Or are they assassins sent to take out one of the PCs? Or perhaps an NPC that PCs hold near and dear to their hearts.
None of these encounters are going to threaten the lives of the PCs unless something goes terribly wrong. They're just going to be part of a fun story.
So - for you DMs out there that use easy encounters in your games - what are some examples of encounters you've run that were 'easy' by the XP standards, but were a lot of fun?
Oftem some bit will have a tie to a pc or story but sometimes it just shows something intriguing like "why did these skeletons kill the adults, spare the kid but steal the toys"???