I don’t know anyone who would volunteer to be shot by a .380acp!
In the same vein of others, I would not want to be shot with a BB gun, bullet of any caliber, or hit with a taser, bean bag projectile, rubber bullet, or OC spray. I also do not want to be hit with a hammer, stabbed with an edged weapon, trip or fall from height, or be in a car accident. The desire to not experience something harmful does not constitute adequacy.
I don't see how a .002" difference in diameter makes any significance in comparing 380 to 38/357.
The diameter difference does not mean much when comparing calibers. What means a lot, especially in terminal ballistics, is the exit velocity, bullet weight, and bullet construction.
While I have absolutely zero skin in the game when it comes to Lucky Gunner, I do enjoy their data.
https://www.luckygunner.com/labs/self-defense-ammo-ballistic-tests/#380ACP
Look at it. They used a G42. You can clearly see that 380acp rides a razor's edge when it comes to experiencing bullet expansion AND having 12" to 18" of penetration. It is more likely that a .380 auto will experience: 1) Bullet expansion and less than 12" of penetration or 2) Very little or no expansion and penetration past 18". Even the majority of those that made the 12-18" window did not expand well. Of all the loads they tested, I would personally only carry one or two of them.
Compare the 380acp data to the 9mm Luger data, where the VAST majority are in the 12-18" window, with expansion. It is amazing what an extra 100-150fps and 25-35gr of bullet weight can do. It is hard to go far wrong in choosing one of those 9mm ammos for carry.
I will not argue extremes, like a P3AT vs a G17/19 or Buffalo bore vs some other "typical" SD ammo. Go toe to toe on similar single stack subcompacts with capacities of 6-7 with similar ammo offerings. No free lunches in physics when a person takes BB velocity data and attests equal proficiency with subcompacts.
Now, from the data, many 380 SD ammos can get expansion with penetration in the 10" range. So the question would be, do I need the extra 2" of penetration? Or said another way, if my sternum to spine is only 8" thick, I'm 2" to the good, right? The problem is that there is no excess. It doesn't account for non-ideal situations. Think about when the media shows the coroner's autopsy reports on high profile shootings. Some officers have fired many more than 6 rounds at a person that was doing them harm. Many of them were not ideal shots. Is any SD situation ideal with the exception of those devised on forums? Perish the thought of a situation in which after someone has shot at you that they have turned and are now somewhat perpendicular to you or they have found concealment or cover. The distance now isn't sternum to spine, but through an object like a merchandise rack, an arm, and a pectoral muscle to get to a CNS location. And who says that bullet is going to travel in a straight line path?
You see where I'm going here. I won't say that 380 is inadequate or should not be carried, BUT - IMHO opinion, too many "ideals" need to line up for it to be consistently effective.
I've hope you've had as much fun reading this as I have had writing. The fact of the matter is that 380's are popular. They are easy to carry and many tuck away in a pocket. They are lightweight and usually lighter recoiling. It's just that there is no free lunch. Concealability, Capacity, and Cartridge all have to balance out when it comes to choosing a CCW.