This sucks! As these things go they've opted for one of the less invasive measures: relying on the user providing a valid credit card, which many will have already provided given Steam is primarily a storefront. It will still unnecessarily hinder people who use Steam credit or a debit card etc.
I did it with a debit card from Revolut, so it doesn't even have to be a credit card or from a major bank.
That's good to know. I'm a little surprised since some places won't accept debit cards for age verification, given they can be issued to under-18s, but then I'm also *not* surprised this system is full of inconsistencies!
In the end, this nanny state nonsense won't "protect" any children and will be a bloody stupid annoyance for everyone else.
An annoyance at best! More likely severe censorship and and a serious invasion of privacy for everyone else, and that's assuming - or wishfully thinking - there won't be any data breaches of sites and services that have suddenly stockpiled a load of user identity data.