Maybe you are confusing .38 S&W with .380, which is a smaller, weaker cousin of the above mentionned 9mm...
Nope, I mean the .38 S&W. Anyone who's been around guns at all knows the .380 is useless for anything except paper targets and bowling pins, but some people actually think the .38 is a good choice for self defense. Probably because it was the police weapon of choice once upon a time.
And for the source of my info, my dad is both a gun collector and a paramedic. After 30 years of patching up gunshot victims he'll flat out laugh at you if you tell him you're using a .38 for self defense. I know because I've had that conversation with him.
Yes, the .38 can kill, but it has lacks that oh-so-important attribute for self defense: stopping power. You will not drop an assailant with a .38. They might die a few minutes after being shot, but that does you no good if they've killed you while they were bleeding out.