I would argue that there is a big difference between a 115 grain 9mm and a 230 grain .40 in terms of stopping power. And the 9mm tends to go straight through.
The wound channel may look the same but was the perp still standing or knocked on his azz? That’s the difference.
The FBI report concluded that the only way to guarantee that you will knock the attacker on his azz is to hit him in the head or spinal column. Whatever the caliber. Most of the time when bad guys go down after a non lethal hit it is a conditioned response. There were a multitude of documented instances in the report of bad guy who kept coming and shooting after being hit center mass. In fact, there are instances of perps receiving a fatal shoot in the heart who kept fighting back for 20 to 30 seconds before they bled out enough to become incapacitated. Whether you agree with it or not the FBI report is very interesting. There's a two part video on youtube that examines this report in pretty good detail which is well worth checking out. I don't have the link so you will have to search for it on youtube.