My initial thought would it would be just making it super easy for their guardians to distribute and control device content. But let the control end at that echelon of power; Not even the local councils or schools should be given the power to regulate social media for kids to this extent IMO, let alone the govt
For some history and related standards, see Wikipedia:
PICS https://en.wikipedia.org/wiki/Platform_for_Internet_Content_...
POWDER https://en.wikipedia.org/wiki/Protocol_for_Web_Description_R...
ASACP/RTA https://en.wikipedia.org/wiki/Association_of_Sites_Advocatin...
The more "digi-ID so we are sure you are old enough, bitte" keeps been pushed, the clearer it's about tracking and not about children. No matter how much they love to frame it the other way around. Unless they want to admit they are total inepts.
Admittedly on paper that means the Gov system would know which sites you were approved for, not logging that would require legislation to not store these logs.