Yeah, I checked out that link. In my opinion, not just no, but "oh hell mother effing no!!!"
It looks like it's worn as a necklace, offering no security or stability at all, other than friction retention. Plus, as you mentioned, it's carrying a gun pointed at your face.
No, no, there are better options out there. I would duct tape it to my wrist before using that thing (don't do that, I'm being sarcastic)