What happens if face ID doesn't really work reliably. If people remember Touch ID didn't at first but back then we only used it to unlock phone and were used to putting in code. Now if application sign-in, apple pay, etc. were not reliable because of new phone etc. it would be a disaster for Apple.
One of the reasons I'm going to wait a while rather than be a first day person
One of the reasons I'm going to wait a while rather than be a first day person