It's fun that one can use games for it, but it shouldn't be difficult to do the same through AI-generated imagery either, which isn't much more difficult.
Even though this method is flawed, one shouldn't really use ID-only verification either imho, as it's a security risk to upload any official document like that (ref. Tea app leaks).
The whole age verification that the UK wants to impose has been quite the impossible task from the beginning. Creating government-backed education for (future) parents about how to raise a kid and protect them in today's digital society would be more efficient than this, if we really are thinking of what is best for the kids. But alas, there are zero requirements to become a parent...