I've had an account there for ages too, because if you are signed in, you can click the button to view a source image at a partner site (as long as you also belong to and are logged into the partner site, if it is a pay to play job).
This is absolutely fantastic, I get the Familysearch search engine/layout, which makes it easy to view a lot of source transcriptions without having to go to new pages all the time, then when I want to check original images, I just click to go to the partner site.
Also, because Familysearch was logging me out regularly, I got Dashlane, which you can use to log in for you. Every time FS wants me to log in, I just watch Dashlane do the work.