That’s because it was designed from the ground up for killing enemies in battle when you can’t access your gun for some reason. I’m assuming 逮捕術 is more geared towards subduing criminals.

There’s a big difference in the way you approach an enemy depending on if you want to kill or subdue. Quite a few years ago, I took self defense classes (it’s an American mutt style. Mainly 空手 and 拳法, with several others thrown in somewhere). Most things we learned were meant to subdue or disengage from an attacker (as is the point of a self defense style), but there were quite a few ways we were taught to brutalize an attacker in particularly bad situations. The one thing that stands out the most to me at the moment involves taking down the opponent and delivering a sharp kick (more of a stomp) or two to the head. It’s assumed you’re wearing shoes, so… Yeah, they probably aren’t getting up. If they do, they will probably be down again before long do to the massive trauma rubber soles will inflict to their face.

The point that I didn’t really make is: If you are just trying to subdue someone, you have to go about it completely differently than if you want the threat to be permanently removed. These two styles focus on only one of these, so they can’t really be compared well in over-all effectiveness.