Most of all, when some misguided soul somewhere in the world guesses or intercepts your password? They still cannot get into your account, because they don't know the 6-digit code that changes Every. 60. Seconds.
(Don't use a Google/Gmail account? Yahoo offers two-factor authentication with SMS and security questions, as does Outlook.com and AOL, well, maybe now is a good time to consider a switch. Just tell everyone your account got hacked!
I hope that helps someone out who comes across this page in the sad, frustrating moments after an email hack. It helped my friend out a bit.