So do you believe child abuse is confined to physical abuse? Do you judge what is happening in this childs life from what you see on a video? There are many forms of child abuse, exploitaion is just one of them, and they mostly occur out of the public eye. She may appear willing, indeed she may even be willing, but we have no way of knowing this. What is happening now with this child will effect her future, and looking at what damage has been done to many other child prodigies, it doesn't bode well for her.
I think putting your child out into the world for public consumption is child abuse, this is a child, not a circus freak.