Why just fight... when you can make a SHOW out of it.
Observing how abilities, skills, and powers work in this setting... I think that attacks like Guy's "flying" barrage of punches and Shaenando's guillotine cross attack being projected are possible because of the music buff.
Like they are taking the sound that is sent to them, directing it, and shooting it out.
Wouldn't doubt the can do it alone, but the scale of the attacks gets vastly enhanced with a musician's help.