And children can get them:

https://www.gohenry.com/uk/debit-cards/

And being on an online-platform is not a right. It doesn't need to be valid form of id to be "good enough" for platforms as an age verification system.

"But children could just get their parents' credit cards" ... and they could also just get their parents' passports.

I mean, in the UK you can get a debit card from 13 years of age so I'm not sure how that helps. Credit cards no, but requiring one would exclude a massive portion of the population as they just aren't as popular.

Frankly, to me that's just an argument against requiring anything to prove your age on an online platform. It shouldn't be necessary and I consider this a bad development.

If it's 13+ that would work if the minimum age for these platforms is also 13+. It's certainly not perfect, but if implemented, it would probably not be the only way to verify your age (or it might if credit card companies are smart and pay the platforms).

Germany has similar simple ways to provide pseudo-verification, e.g. they'll use direct-deposit or direct-debit to transfer a cent or three and put a code in the subject field that you'll need to enter. It's not perfect, and they wouldn't even know who you are, since account numbers aren't tied to names, but it proves (sufficiently for them to say "we really tried") that you are the account owner. While they don't know who you are, your bank has to because of KYC, and in case of trouble they could say "talk to the bank, they know who's hiding behind this username". Of course there are edge cases and ways around it, but it's enough that they get out of hot water.

I don't really have an opinion on whether age should be verified. I'm past most minimum ages and I don't have children, so I'm not affected.

Go Henry describes their debit cards as "perfect for kids aged 6-18". My son is 13 now, but he's had a Go Henry card for years.

https://www.gohenry.com/uk/debit-cards/

There is no minimum age to get a debit card in the UK, 13 just happens to be a common limit imposed by the banks themselves.

Or they will just use platforms outside of their governments control.

Like is a platform run out of China going to care what fines the UK government threatens.

Possibly, but the same argument can be made for GDPR, and it works pretty well there. In the end, the Chinese will either want to monetize it, at which point they need a presence in the UK, or they're monetizing via psy-ops paid for by the CCP and they will be considered a security issue by the UK and probably shut down (at least for access from the UK).

Sure, that might lead to teenagers using VPNs to access it, but I wouldn't count on that. Most of them aren't even using adblockers.