You know how you can throw a frisbee at an angle that makes it come back to you in a straight line?
An angle that you can easily hit if you try to throw out of a trench...
Stacks nicely in a backpack? You know how much crap goes in a medium ruck? How's Jenkins gonna find my stash of disk nades under my spare ammo and 'field stripped' MREs? No, I need my grenades quick access, on my chest next to the repurposed saw pouch full of rip-its.