there are internet filters you can buy
Seems like that's exactly what this is, it's a mode that you turn on on the phone and it uses a government supplied list of vetted websites for the kid to visit.
Interestingly the way this feature set reads out is exactly the same way that Nintendo's parental controls work.
I realize that this being the Chinese government, them keeping usage stats has connotations that go beyond the data itself... But in a country with a more liberal government I'd rather have them keep records of my kids' internet usage than a private company. The idea being that you can pass protections around that data. (Not that that seems to be stopping the current US government so maybe that's a pipe dream).
Ideal is, of course, completely on your own hardware (the device or your server at home), but between this and a system where Apple/Google/Nintendo does all this instead I'd prefer the government method.