Jamming a pistol into a cheaply-made tangle of elastic and nylon webbing while it's pointed at your brachial artery? What could possibly go wrong?
Call me a big ol' scaredy cat, but I think I'll pass on that one. Plus it doesn't even look comfortable. (Further, unless you're built like CGI Hulk, any pistol small enough to be velcroed to your biceps is small enough to be carried in thirty-eleven other places that aren't dumb...)