How to Login with G+ account to Chat when Chat only available in Admin

Hi there,

I'm a little confused about how to allow users to login with their G+ account if I only allow chat in Admin side.
When I installed the Ultimate Facebook plugin, it added a "Login with Facebook" button to login screen. I thought something like that would be added to login screen for G+ after I installed and configured chat. However, there is no option to login with a G+ account.
I've created the G+ API stuff as per the instructions and entered the data in chat settings. See screenshot.
So what I'm guessing is that in order to login with G+ to Chat, I need to put the Chat on a publicly viewable page and then there will be an option to login in with G+?

What happens when the Chat is only available in the admin section? User needs to create an account first...can they create an account with their G+ account?

What I'd really prefer, is to add a "Login with G+" button, just like the facebook button, so that users can create accounts through their G+ profile.

Do I understand the behaviour correctly?