It is a fairly common perspective, and it ignores some of the realities. Even if I'm not traveling, in NC there are a ton of places I can't carry. Nowhere people paid to get in (movies, theatre, opera, museums, etc.), anyplace anyone puts up any kind of sign (last I looked the law allowed a pretty wide range of signs) that disallows them (and many retailers do), anyplace that serves alcohol (I think that's right, it might be anyplace that has a bar). And when I'm working on a client site, I'm generally subject to their policy manual on most matters, including that. So, even when I'm not traveling, I am very restricted as to where I could carry, even with a permit. And with all those limitations, it'd be difficult to justify carrying most days (since I'd have to keep taking it off an leaving it in the car). Without consistent carry, the gun isn't an especially useful tool, since we can't predict when and where we'll need it.
And I'd be skeptical of the idea of a gun's usefulness in a lot of types of defensive situations. Like you, I haven't seen data that really supports how effectively it can be deployed, and any data we did have would be hopelessly confounded by the user's level of training and preparation.