OAuth is powerful and awesome because even when people hand over full control they can revoke that access at any time they want.
Previous to OAuth people would hand over their credentials to third party apps. That's what sucking looks like.
Previous to OAuth people would hand over their credentials to third party apps. That's what sucking looks like.
2) Or unless you wanted to let some apps keep access to your account, but not others.
3) And if you can easily deal with remembering new passwords (most users can't).