Voice isn't supposed to store anybody's ID information, only a hash of that information for the purposes of enabling Proof-of-Unique-Human. It actually protects your identity until someone suspects a certain ID-hash of being the result of your identifying information being collected and hashed using the process that Voice uses. Then that suspicion could be verified by law enforcement, for example, or a court of law for the purposes of proving ownership of a digital asset or rights.

If I recall correctly, the identification app uses national ID information, facial recognition and fingerprints.