In the past many "Gun Rag Experts" debated whether the 38 Special or the 380 were the minimum floor for a self defense round. On paper the heavier slower 38 Special was often given the nod as it had 10 whole ft. lbs. muzzle energy over the 380 and due to its heavier bullet was expected to penetrate farther. Of course many of these experts also didn't consider the power loss that came about when you used a snub with a sub 2" barrel. Lighter faster vs. slower heavier....guess what in a non expanding bullet they both make the same sized hole.
Then came the first two generations of hollow points. Mostly a concession to the market want for a hollow point bullet with the added issue that many guns available in 380 wouldn't reliably feed a generous diameter hollow point. So you have bullets that will feed well but expand poorly if at all. A 38 Special had no such problem with feeding so the makers could easily make a bullet that would work well. There was also a smaller demand for 380 ammo so little effort was put into improving the bullet designs and the lesser demand also kept the ammo cost up; further depressing demand.
Then came the proliferation of Shall Issue CCW laws. Lots of people found suddenly that a 45 auto looks great on paper but not so great when dressed for places like the Southern States in Summer.
Suddenly many people found that the saying that a 32 in the pocket beats a 45 in your dresser really meant something. The 380 found new popularity.....and the market took notice. New efforts have been put forth by the manufacturers to make better ammunition that both feeds well and expands more reliably. They even try to balance that with penetration.
In most cases where a gun needs to be used, if a person presents and the bad guy believes that he WILL
get shot the encounter ends without the need to actually shoot. The gun has successfully neutralized the threat and stopped the bad guy. In the other cases if you must shoot, you need to hit. When the bullet fly, the bad guy will probably flee...if so the gun stopped the bad guy. If you hit and wound the bad guy and he stops doing bad things; again the gun worked and stopped the threat. If you hit and the bad guy dies; threat neutralized permanently.
Can the 380 kill???? Yes. Can it "Stop" a bad guy???? Yes. Can it stop with one bullet???? Yes but that is asking an awful lot from ANY
8 hits from a 380 beats 5 misses from a Scandium frame 357 any day; I don't care what ammo is in it.