Yeah, the DID you receive from the attestation service can be used multiple times, and is assumed to be immutable, so you sign messages with your private key to prove ownership of the DID but generally reveal no other information. One concern would be that a backend integration might exist between the Australian government’s attestation service and Google’s system, in which case there might be benefit to the existence of an alternative public institution that is committed to privacy which has the demonstrated authority to verify age.