When I read this I thought -- oh man, I hope Apple doesn't decide to somehow limit this feature in the future. I wouldn't be surprised if it's already against the terms of service somehow to deploy a 'beta' app and then just keep using it forever. (Besides, don't you have to pay to be in the developer program? That may be somewhat acceptable for some adults, but kids whose parents would prefer that their kids "study" instead of "wasting time playing computer games"?)
Anyway, this is one of the reasons I use Android. While becoming root isn't realistic on many devices, I think it allows you to do enough for kids to find their way into programming. Maybe the challenge of getting a root shell/flashing your own OS is enticing to some too. And maybe the tech used to protect devices from their users is interesting to some people too -- and since OEMs need to know how all this stuff works, it also happens to be documented pretty well. (I think this tech is still in its infancy unfortunately.)