I cannot believe we are posting among such newfags that dancing in ops is a "recent trend thats played out" to them. Do they also not know that ever aspect of anime is designed to be viral, trendy, promote doujinshi, cosplay, fandom ect to get people to buy mangas and bds???? Every single cut of animation you see that looks loopable is made that way so people will cut it out and post it everywhere, every op is trying to build synergy with some new trendy band or artist of musical movement in japan. Its all by design, of course there's gonna be dancing in ops so that can catch on and spread everywhere.