It's not really a studio tag it's more of a blanket tag for beatmania/popn/ddr/guitarfreaks but I'm not sure if we actually need it as a tag at all as the games are only connected with a common theme (rhythm.)
Well, even then it doesn't have the same problem as a franchise -> publisher implication because bemani will always be the division that created them, that can't change hands.
I'm not necessarily against umbrella tags but this one doesn't seem to represent a particularly significant common theme, does it? That is, there's not a lot connecting the various franchises.