It's an interesting statistic and probably is good guidance for anyone else, even if only seen as "Carry a 9mm Glock or M&P with some emergency medical supplies, and you can't go wrong." I'd certainly agree with the statement. Generalizing to "carry something that's got long-term reliability, and train regularly with it" is just as good. The one guy carrying the Beretta is no worse off than the 5000 carrying Glocks so long as he's trained with his Beretta, and they've trained with their Glocks.
Would you rather be punched by Schwarzenegger or Ferrigno? You're screwed either way as long as he's been training
However, Berettas are sexier and it's been scientifically proven, in lab by guys wearing goggles. That case is closed!
I did once hear a rather...strained...argument that would basically look at this data to say "Yes, those sorts of guns are great
for people who train all the time, like these instructors who won't make careless errors, but normal people who can only get to the range a few times a year should carry a double action .357 mag revolver."
I think his point was that revolvers are usually the most reliable things on the planet, you'll probably only get off a shot or two at close range, so make it count, if only 1/5 of your shots will land anyway, better it be a .357 mag than a 9mm. etc and so forth.
Interestingly, the guy who made that argument carried a Glock AND a snub-nose .357. Oh, and medical supplies.