I don't have one but I know why I'm attracted to them. "Back in the day" as they say, Mattel made a belt buckle with a pop-out derringer that I just loved. It was spring loaded and when you pushed your gut out, the gun would pop out on a hinge and fire a plastic bullet with a cap (if you had a greenie stickum cap of course). I thought that was SO cool. Of course I forget that the gun would go flying off the buckle about half the time, but the idea was cool.
The NAA always reminded me of that. I keep saying I want one.