It would be preferable if the prover party that holds the credentials in this scenario weren't Google. If anything I'd prefer a government issued digital ID wit

It would be preferable if the prover party that holds the credentials in this scenario weren't Google. If anything I'd prefer a government issued digital ID with some form of local-only cryptographic exchange where neither the government knows someone has verified at a particular site/service and the verifier doesn't get info about one's identity. Just some cryptographic proof that verifies an age ('just' is doing some heavy lifting). In past HN comments this apparently exists IRL in Germany and/or Canada, where age can be proven via a smartphone without leaking one's identity to the verifier and without any communication back to the government.