That's just it though, if they come back when you overfeed then they never really went away completely.
Unless you are adding new plants or something to bring in fresh specimens. It only takes 1 to repopulate an entire aquarium once they get more food available.
They don't do anything to remove ammonia or nitrates though, so there is no real benefit to having them. They feed on floating particles in the water, algae and tiny bits of food. They're basically a small form of freshwater anenome. They don't actually hurt anything either though unless you are keeping shrimp or are breeding fish. They have been known to kill tiny shrimp and fish fry.
As you said though, not overfeeding keeps the population low enough that you probably won't even notice them unless you get a magnifying glass and start inspecting your decorations or plants.

They don't do anything to remove ammonia or nitrates though, so there is no real benefit to having them. They feed on floating particles in the water, algae and tiny bits of food. They're basically a small form of freshwater anenome. They don't actually hurt anything either though unless you are keeping shrimp or are breeding fish. They have been known to kill tiny shrimp and fish fry.
As you said though, not overfeeding keeps the population low enough that you probably won't even notice them unless you get a magnifying glass and start inspecting your decorations or plants.