Swift is coming with this default set-up for anonymous user checkout.
So, it means, if someone knows existing user email, they can just change user data during anonymous checkout without logging in.
Looks like anonymous user can't change password or get access to user, but ability to change address, name or other user fields without having user access sounds like a security breach.
Probably this option should be used very carefully instead of being default option in Swift? What do you think?