You mention COPPA and GDPR but which country regulation do you cover (and in which language?). How do you ensure that the Parents giving consent are the parent of the child (and that you are not getting spoof?). How do you keep up with the changing regulations, with some country having multiple layers (Union, Federal, State, City, ...).
I like the focus on Childs, but you could also extend it to do KYC for financial institutions, the market may need a cheap and reliable solution.