I find most of the clips of kids performing belly dancing very icky no matter how talented they are. Unless you are VERY careful it is age-inappropriate, and there are so many pervs out there that even appropriate stuff is going to draw the wrong kind of attention.
I don't think there's anything wrong with kids having lessons for fun, or to go to events with mum when they are old enough if they want. If my daughter wanted to learn and my teacher did kids classes I'd be fine with it because I trust her attitude, but some teachers...
, maybe not. And performing is a minefield, IMO.
I think competitions where girls are expected to dress and perform like grown women are repulsive and exploitative. Responsible adults should be protecting young girls and guiding them until they are of an age to understand what they are doing and the effect it may have.
<Mother speaks: You are not going out in that skirt>