Why would I ever trust a notary?

As a person being notarized it sounds like I have to give that business more personal information about myself than I usually have to do to get an online identity, as suggested by your subpoena statement.

As a service trying to verify accounts I now have to trust a third party. Maybe the notary has a business that sells fake IDs in the back that are then used in the notarizing process. Maybe my competition set up a burner notary node in order to flood my service with malicious accounts. It sounds like an attack vector.