And Sir Thomas, aware of this, said that the divine wisdom was above all to be compared with games because games are played for their own sake. And not for any sort of ulterior motive. So also music is a kind of non-purposeful thing because you don’t either play music to reach a destination, nor do you dance to reach a particular place on the floor.
So the idea is that the that dancing and music (more than other arts) represent the nature of this world.