Cite your source, please.
I did--most of the defensive shootings I've read about over the years required no more than one or two rounds, so it's anecdotal. I never intended for it to be more of a formal proof than that, as the OP wasn't trying to strictly prove anything, either. My point was really that a response to the OP's casual suggestion appeared to be addressing a somewhat different (but definitely related) issue.
I would. For example, I don't care how "comfortable" someone feels packing a 5-shot NAA, it's still not a good choice for defense.
It's not the best choice for every situation, but as for whether it's a good choice overall, that depends on how you define "good," and it's certainly a lot better than nothing. You don't consider it a good choice, and that's just your opinion--I don't either, but that's just my opinion. These are merely opinions rather than fact because even an NAA can kill or scare away bad guys, let alone a .38/.357 revolver like the SP101--we're not talking about spit wads and a straw here.
Is it better than nothing? Maybe....perhaps even probably, but only if the user fully understands the limitations of such a choice.
Probably is all that is required to handle
most threats, and nothing you could propose (that is practical) can handle ALL threats anyway, so naturally the issue of ammo capacity comes down to a matter of degree and individual preferences.
But those that DO fully understand choose something else.
I think that a full understanding of defensive handgun use includes the knowledge that the differences in effectiveness between handguns is not nearly as great as many people believe. Sometimes even a small advantage can mean the difference between life and death, which is a point that I've brought up myself on a number of occasions, but in the big picture the difference is still small (even when including the NAA mini-revolvers). That is why there is such an emphasis on shot placement on this forum, for example. Also of great importance and practicality is choosing a gun that you can carry all the time (in the case of CCW), and one that you're good at shooting, even if that means resorting to .22 LR for some folks--proficiency and confidence are more important than caliber, in my opinion, although like ammo capacity, caliber still counts as a secondary consideration, with load selection being more critical than the actual type of cartridge.