The only snails I have are Melania, two species. If I had snails that munched holes in plant leaves (like my Striped Botia do, but let's leave them be) I might feel differently.
My thought about snails is, what's the alternative? Snails represent a certain amount of nitrogen, calcium, phosphate etc., and they fulfill a role/fill a niche, processing detritus that is in particles too large to be handled by fungi and bacteria.
So, if there weren't snails in the tank, what would take their place? Flatworms, largely, in my tanks, I think.
But "Life will find a way." If the nutrient opportunity exists, it will be used. Better lots of little snails than lots of little planarians eh