What if you don't have a credit card? This solves nothing, the good way to do this is as system like Polish "MojeID" (my ID) [1]. This works in the following way, a site needs to verify information X, then it redirects users to a bank (that has to provide this service), login over there and then agree to let the bank know whatever it was requested - it could be only one information, birth date.

This is a good solution, as banks are obliged to provide free bank account for anyone (there is EU regulation on that), this is very save, gives users full information what data third party requested.

[1] https://www.kir.pl/nasza-oferta/klient-indywidualny/identyfi...