OpenID, Facebook, & Twitter don't provide a users email. (OpenID might - but you still have to verify it's legit). SwiftLogin just off-loads the email verification for you (and in turn, every site after you) so that you can just let them in right away.
Actually, that's not really possible because most people who do this chose simple passwords under 8 characters. SwiftLogin requires much more complex passwords to even create an account.