It's all a trade-off.
I personally don't want to know how good or bad my shot placement would be in a self-defense situation, but I'm not going to bet on the best possible accuracy.
However, I also don't have a large caliber; I shoot a 9mm. But I like two things about it that I think balance out the firepower vs. accuracy imperatives in my case.

1) Higher mag capacity---knowing that if I get in some sort of a shootout situation I won't be so likely to run out is good. If someone is drugged up and doesn't feel impacts, I have more to spare. One thing I don't like about .380s or .45s that only have 6+1 capacity is they don't offer this.
2) Less recoil---I'm pretty thin, and perhaps more importantly, for want of practice not quite experienced with containing recoil from larger cartridges in the sub-compact frame. Being able to get back on target faster at the range than I could with a .40 S&W or larger encourages me to think the same goes for a real-life situation. I won't carry a full-size for concealed carry, so whatever I can shoot in a sub-comp frame without completely losing sight picture is what I'll go with.
Perhaps for some, that means shooting a .38 Special, and a lower-grain bullet at that. More power to them; it's better than nothing.