It's always smart to assign a password to your account. Github was down just the other day. Keep a password assigned to your account just in case. By the way, I think github is a great single sign on for hacker related services. People who use parse are usually already logged in on GitHub... Right?
Implementing GitHub login is no more valuable than offering Facebook login. It ties things to a single identity provider and limits the number of people who can use it (ie: no FB/GH account, no ability to use it).<p>Why not implement Mozilla Persona instead?