[danillonunes]

Also, let's be honest, outside of some loud privacy concerned voices, most people don't care and they will prefer to scan their faces with the phone they have at home which is an action they are already used to do than to spend money to buy some nerdy device.

[necovek]

Phones have the nerdy device built into them too (secure elements/TPM chips) — it should be pretty easy to have the TPM-based key verified by the government once.

But even if it just confirmed adult vs under 18, it would allow for easy segregation and building a database of kids.