Don't discount the little guy...
Once pulled out my Single Six and shot a water logged 4x4 fence post. The 22 Mag round just popped right on through. So I decided to see how big of a hole I could blow out of the backside with my Blackhawk. I was shocked. The 357 Mag round never made it through the fence post.
So I'm guessing the 22 Mag might be good for poking holes in your attacker.
But I'm also guessing that my 380 will deliver a bit more shock, even if it doesn't penetrate as far.
P.S. With 6" barrels, my 22 Mag revolvers don't make good CCWs.
A couple of DT 158 GDs will do it!