While the boxes are rolling in

What's up with all the dancing. Seriously, I wanna know. Why dancing?

I understand the need to fluff up a illusion show in order to hide the fact how little material there really is. But there are so many other options. Like juggling, singing, comedy, some feat of skill, a cool story, a laser show, poetry, martial arts or a music performance.

My theory: The assistants are dancers. And they only agreed to work in the illusionist's show if they can show off their stuff as well.
But my theory falls apart, when seeing that singing is often fluffed up by dancing as well.

Opinions?