Well I guess not entirely useless I suppose… you be the judge:
.50 BMG Proof iPhone Case - If your pockets are big enough, and your fear of taking a round to the femoral artery is more of a concern than your coolness.

$650 USD at this sketchy Japanese site
And finally…
Knuckle iPhone Case - If you’ve ever wanted to send a text message and a physical message to someones face.

$99 at Knucklecase.com
Thoughts?
For those times when you need to punch-shoot an attacker:

Smart. That’s Colt really paying attention to the CQB needs of the average concealed and open carrier.
You might ask, “What’s wrong with pistol whipping?”… to that I say: punching with these knuckles puts a lot less stress on the internals, and also keeps you from muzzle sweeping yourself and others. Plus, with these 1911 knuckles you can punch-shoot with great accuracy