So this was a little different, not frequently utilised by most lifters but the @fatgripz do have numerous benefits for pressing as well as arm training.
They strengthen wrists forearms/ grip - all buzzwords if you train heavy frequently.
They disipate force - benching all the time w/ normal bar can create elbow/wrist pain for some lifters. especially when you start using heavier weights. the fat bar takes some stress off of the hands/elbow/forearms.