I have the .22mag version. I call it the Noisy Cricket. I like it. More of a novelty and convo piece than something that serves any purpose for EDC or self defense.
If there's anything you should know, it's the fact that it SHOULD NOT be shot by an inexperienced shooter. The thing is very jumpy, at least my .22mag is, and IMO in the wrong hands can be dangerous.
Also, are you aware that you can carry it with the hammer dropped in a way such that it is not resting on a round, but sitting between two rounds? Makes it much safer to carry.
If you want a tiny Derringer like gun to carry in a pocket, consider the big bore derringers made by Cobra (you can get those in 9mm and .38). While the .22mag is a nasty round, I'd rather carry a 9mm or .38 for EDC self defense for several different reasons.