...hmm. All that, and yet still doesn't have the most essential accessory of all. A sling. I guess he just does bicep curls with it while he carries it everywhere.
Context. It's all about context. This weapon is not designed to be used as demonstrated in the video -- "hip sniping."
Imagine a "Walking Dead" scenario ...
A couple of idiots have stirred up a hornets' nest of zombies, have used up most of their ammo and are now hiding in an abandoned construction trailer, desperately holding the door closed and barricading the windows against the zombie hoard. They know they're goners.
You, however, are sitting in an office building across the street, about 100 yards away (perfect distance for the middle optic, although the other two will easily cover the 200-yard and 300-yard ranges if needed), calmly munching on some Cheetos and working hard to keep from getting orange slime on your ZombieKiller AR. While watching the Bears lose. Again.
After you're sure that the idiots are out of ammo and are nearly out of time, you calmly swing your ZombieKiller AR, supported by its bipod, in the direction of said idiots and turn on your lasers, just for effect. You never know when some zombie might be using a cell phone camera and you'll make the 6:00 news.
BAM. You watch the zombie's head explode with a perfectly placed headshot. BAM. Again. BAM. A little high. *sigh* Fun, but boring a few mags into the game. At least YOU won't run out of ammo.
One by one, the zombies pile up and you've picked off the wandering squirters with your secondary and tertiary optics. Just for fun, you zing one round into the corner of the trailer to let the idiots know that you've saved their bacon once again with your ZombieKiller AR and return to the game.