I guess we have like, Improvisation, Shield Samba and Curing Waltz, that are dances with different effects than 'does damage', they just... don't require pressing dance steps to activate. In the devs defense on this one, I can't imagine it'd be fun trying to put up Shield Samba in time by doing a 2 step dance like Standard Step, not to mention it'd be on the GCD like that and therefore a DPS loss