The new facebook login allows you to choose what you share with your friends or public or you can skip sharing completely.
With the new facebook login, you decide which apps can share with your friends. You can skip sharing altogether.
With the new fb login, you can login to your favorite apps with just few taps. You dont need to fill out long forms and remember the usernamd and password.
Facebook login is a great way to use integrate in websites. It provides a secure way of logging into the website.