Neildo is partially right, with the human opponent it would be enough for me if he was blind for a while. With one movement I can break a leg or rip air canals out, but that's not the main point. The point is that I want to minimize the time of contact as well as minimize the risk of that contact. Gas pistol seemed to me to kinda maybe serve that purpose.
I don't want to get into trouble with a real gun. On the other hand I could always aim for the legs in the case of a human.
As for misusing handguns, I've spent a large part of my childhood with the military, and lots of that time I was practicing with various pistols, revolvers, rifles, machine guns and even a few heavy machine guns, so I know my way around.
But as I said, I'd like to have a non lethal weapon.
p.s. I don't need a gun for home defence, I need a tool for hiking against rabid farmers and their stray pets.