I work in healthcare in the US, and using banks to perform auth is a fascinating concept. I also don't see the US ever adopting it due to nuances in American concepts of privacy. We don't mind sharing literally everything with a single entity, but once you get more than 1 entity involved, everyone freaks out. Using banks for auth would also eliminate the wide array of third party auth services, like Auth0. Eliminating the middle-man is very un-American.