[spicyjpeg]

While great on paper, zero-knowledge-proof based systems unfortunately have a fatal flaw. Due to the fully anonymous nature of verification tokens, implementations must have safeguards in place to prevent users from intercepting them and passing them onto someone else; in practice, this will likely be accomplished by making both the authenticator and the target service mobile apps that rely on device integrity APIs. This would ultimately result in the same accessibility issues that currently plague the banking industry, where it is no longer possible to own a bank account in most countries without an unmodified, up-to-date phone and an Apple or Google account that did not get banned for redeeming a gift card.

Furthermore, if implementers are going to be required to verify users per-session rather than only once during signup, such a measure would end up killing desktop Linux (if not desktop PCs as a whole) by making it impossible for any non-locked-down platform to access the vast majority of the web.

[squidbeak]

I'm unsure how applicable these risks are here. The proofs appear to be bound to the app, which in turn is bound to the user's face/fingerprint (required to unlock it).