One additional annoyance with this type of login: With a username and password field, these are automatically correctly filled by Safari. With sites that only

One additional annoyance with this type of login: With a username and password field, these are automatically correctly filled by Safari. With sites that only offer an email field, I have to manually fill it. (Note that I tend to use different emails for different sites; if you only ever use one email this might not be a problem).