I have carried a J frame snubby as a sole firearm a few times. Don't like to, for lots of reasons. A small revolver like that is much harder to shoot well, and in a case such as this it is even more important if that is possible. Given the ballistic reality of handgun rounds, unless one scores a good CNS hit, the odds are that it will take 3-5 shots to slow, then stop, the assailant. Being empty and needing to reload at that point is well below optimal.

My G33 is 9+1, and I carry a spare mag. That is far more likely to be useful, but it is probably more unpleasant to shoot. I carry it most in settings where being discrete is a high priority. If that is not an issue, I stick with a full size 9mm (chopped G17) and a spare magazine. I have actually followed the research, and don't know anyone who wished they had less ammo when the excrement hit the oscillating device.

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NHI, 10-8.