Modern gun people say "Yeah, it fires a 'pistol round' of sorts but it was doing 1900fps.  It was as powerful as a .357 Magnum!"  I'm sorry, but velocity is not everything--it was still a full metal jacket .31 caliber, which we know is not much of a manstopper in most forms.  A .357 Magnum is a different round entirely--.36 caliber, and in man-stopping form fires a bullet with an exposed lead nose, usually pre-stressed to separate upon striking its target and expand.  Even so, would you try to kill a bad guy with one at ranges much beyond 50 yards?  Not without a lot of practice.

Which leads to the next bit of praise for the Carbine--it's a lot easier to hit with than a 1911 pistol.  Okay, but at what ranges are you expecting gun crews, etc., to fight the enemy?  I call this a failing within the U.S. military.  Train the troops to use the pistol!  Quit resorting to the lowest common denominator!  I've read many stories outlining the reality that the pistol became a badge of office, which was never the intent.  Okay, "badge of office" isn't the correct term.  How about this?  Especially for troops expecting close quarters combat--this was a common concern on the Pacific--everyone simply wanted a pistol.  If a 'Nip' jumped into your foxhole in the middle of the night, your survival odds were much better if you went to sleep with a pistol in your hand.  A Carbine didn't offer the same sense of extreme close quarters security.

Ultimately this story reads like one written by someone who had never researched this topic before and had decided to take the first things he found and publish it.  Sorry, but a few decades of reading about this topic gives me a different viewpoint.