That is indeed an interesting study, guns are even more effective for self defense than I thought. But that still doesn’t remove the possibilty that you encounter someone (or one of those groups of up to 7 mentioned in your study) that is more determined (or numerous) for whatever reason, which would necessitate a larger (standard) capacity magazine. While it may be statistically likely you’ll fire less than 10, if you do need 15 for whatever reason then statistics will be of little importance as your gun runs dry during the defense.
I was going to compile a list of incidents where more than 10 shots were required, but I’ve been really busy for the past few days, if I have time this weekend I’ll try to compile a few and edit this, but you can also do the same by just paying attention to it gouing forward (but I reccomend videos over articles if you can find them, sometimes they shoot more than they need to, articles could skew it my way.) They do happen, even if it isn’t statistically the most likely, and when it comes to life or death it helps to cheat the odds in your favor any way you can, like by carrying a reasonable amount of ammo (too much gets heavy.)