Ahh! With the change of scenario from self-defense to defense of others, you have completely changed the panorama relative to the concealed carrier. This will probably draw criticism, but it needs to be said.
Seriously, take a long look at the targets that many of the new shooters display on the internet, and these are most likely motivated by their perception for a need to defend themselves. I'm not trying to discourage them, but the demonstrated skill set could probably translate into a marginal qualification on a Q target. This is most likely someone that SHOULDN'T consider engaging a threat "in defense of others".
Hopefully, those of us here have a stronger skill set. How many of us can shoot a fist-sized group at 7 yards? Can keep our shots in the aiming black at 25 and 50 yards on regulation Bullseye targets, or keep our shots in the K5/9 ring or better of a B27 or the old Kill/Disable police targets?
This is where we need to look at the CCW-holder's experience level. Many of us here are most likely current or retired LEOs or prior service. Marksmanship was a strongly developed survival skill. For others, we may have a long or varied past in different target shooting games. While I am prior service, I have a long and varied past in competitions. I started shooting 2700 bullseye, then IHMSA. Prior to that, Jr smallbore rifle matches. Now it is F class matches with rifles out to 1000 yards and GSSF/ ShootSig/USPSA/2700 bullseye matches.
Looking at the Walmart scenario, your CCW gives you the permission to carry in order to protect yourself and your loved ones. Your CCW is not a hunting license to allow you to play a LEO! The nice thing about having shot IHMSA, is that it showed me what I was capable of, and more importantly, what I wasn't! Would I attempt a long shot with my P365? Only if it didn't go past 50 yards! I like to think that I know my limitations and those of my equipment.