I'm not convinced. When I think about kids or my childhood, it tends not to involve hanging out in places with a decent surface to project on and semi darkness to get a good image (or if they are in a place like that they've got access to a TV).
Perhaps when the tech has improved (both sound and vision) this becomes the replacement for the TV in the kids room - just plug it into a charger and project it onto the wall streaming over the net - but it doesn't feel like a mobile thing for them.
Remember, while this tech improves so do other displays. The expected standard will go up and the price of competing products will go down.
When you can have a large screen, hi-def TV in every room that you can wirelessly and effortlessly connect a mobile device to, which comes without the issues associated with projection (shadows, light and so on), why would you want a projector?