Where three points really shine, is when you work with a rifle slung for a job.  They can be rigged a few different ways, slung a few different ways.  I.E. slung one way, the rifle falls to the front, the other shoulder you can throw it away from you and it zips back and around behind you and kind of cinches in so you can mess with stuff or people on the ground without the rifle dangling all over.  Mine is set up so I can also use it as a parade sling" and even as a hasty support sling like a traditional sling.