I am the person who sometimes carry an unchambered keltec. I also have an sp101 in .357 mag and sometimes carry it. I have a Beretta tomcat in .22, but never carry it because the keltec is lighter, and in my opinion safer. I also have one of the NAA .22 revolvers and it is smaller and lighter than the keltec, which is already pretty tiny. I think it's wonderful that little ole me can have firepower starting at the NAA .22lr and going all the way up to an 8mm k98 or 12gauge, and a fairly representative sampling in between. The NAA is lighter than the mauser, but has considerably less firepower, it is much easier to conceal also, but harder to mount a scope on. Imagine that, different guns have different strengths and weaknesses.
The fact is more is more, even if it's only a few ounces it's still more, and sometimes even a few ounces is the difference between having something in your pocket and having it in the glove compartment of back at home in the safe.
I have dispatched literally hundreds of farm animals with a .22lr revolver, granted it had a 6" barrel and not the tiny 1 inch thing on the NAA, but in over 40 years of watching farm animals go down, or doing the shooting myself, I only remember one time when we had to shoot twice. In that case the steers skull was actually a skull within a skull, very wierd. So I would suggest that the .22 can not penetrate two bovine skull depths of bone.
At the end of the day a gun shooting nothing but blanks is going to be effective the vast majority of times. In fact, considering the general bloodthirstyness of people on this forum blanks may be the best choice of defensive ammo. Must less chance of going to jail for manslaughter that way and the odds of shooting the wrong person are not to be taken lightly.