Ultimately, the point of hardware attestation isn't to ensure that your device is trusted, but that the action you're trying to perform was done by a human, not a bot doing millions of them per second. It's just another CAPTCHA mechanism in disguise, required because bots have gotten so good at solving the existing ones.

With a secure device, the only way to get an attestation for an account signup is to do the signup on that device, with real fingers clicking real buttons on a real screen. There's no way to short-circuit the process by automatically sending a JSON request and bypassing the actual signup flow from a Python script, like you can do with an insecure endpoint.

With blind signatures, a single compromised device destroys the value of the entire scheme, as it can be used to issue an infinite number of attestations with 0 human oversight.

What we need is a blind signature construction where the verifier can revoke a signature, each signature carries proof that none of the revoked signatures comes from the same signer, and where it is impossible for one signer to issue more than n distinct signatures during one time window. Not sure if this would be possible with ZKPs; my cryptography knowledge doesn't extend that far.