Other auth method will not provide this (maybe LDAP but for sure stuff like pas.plugins.authomatic) but in those cases users are created externally so it's OK imho that this feature is not supported.
Instead Plone could implement this.
A recent usecase: a customer leaved the join form open without capcha and this time it was not simple to get which users where fake or not. BOT attacked all night long, having creation date was an important missing information that time! 