It would be far more useful to have a feature akin to how FIDO authentication works where the app sees something like Hash(userID, appName). That way you can tr

It would be far more useful to have a feature akin to how FIDO authentication works where the app sees something like Hash(userID, appName). That way you can track a user within an app, so if you install the same app on your iPhone and iPad you don't have to make a separate username/password combination to get access to your saved data. But you can't track people across different apps.