> but the implication is that the government now sees what you are using.

No. The whole point of privacy preserving technology is that they don't.

The idea is that the government checks your identity (they know who you are) and give you an anonymous cryptographic proof that you are above, say, 18. They don't know what you do with it.

You give this cryptographic proof to Discord, and they know that if you have access to that proof, then you have access to someone who is above 18. They don't know who you are.

Sure, you could ask an adult to give you a token. But you can also ask an adult to buy you alcohol or to do the age verification scan for you.