It could be a good intimidation tool for stick ups. All it takes is one shot so most people will be scared enough to comply as they would when faced with any other gun or weapon.

On the flip side, the barrel doesn't last fore more than one or two shots if you're lucky. You can't reload fast and have a single shot. I can see it being a useful tool for an assassination. But that single shot better count otherwise you're either captured, dead or you lose the target.