What does the Security Suite do and how do I use?

Maybe I’m blind but in the Wiki there’s nothing at all on the Security suite thing that SuiteCRM has. I’ve been playing with it in SuiteCRM but what exactly does it do? Does this provide field level security or? Is there any info on how to use it?

You can browse to SecuritySuite for comparable features and functionality.
Watching the video made me understand the concept.