This knife is not used like a karambit. The guys showing how to use the knife have trained in many types of martial arts as well, including blade based arts, and have used blades in real world encounters.

Full disclosure: I have trained with and taught with all of the demonstrators in the video. The point you make about having fingers, etc broken is a point that could be made of any type of encounter. You don't have to like the blade, but most of your points are not specifically related to the blade, but personal protection in general.

Legs being exposed to what? A takedown attempt? if you want to try that on someone with any blade, good luck. A stick attack? Maybe. but then you are talking about different situations. Interecpt the hand? Not likely either. Real world knife encounters don't look like movies, and don't go like any rehearsed templates or forms.

The Colonel was designed to be a blade to put in your hand and punch with. No major training or years invested to truly know how to use it. Is it an answer to everything? Absolutely not. It is very effective for it's intended purpose though. A lot of real world people are carrying these. Even Paul Howe recently wrote about it in his monthly news letter.