Actually that blade style is supposed to be a great “fighting” blade. Unlike a conventional blade, the Seax won’t slide out of the cut but slice all the way to the tip. So says “the experts”.
This was my understanding, that it was meant purely for fighting. Your description makes a lot of sense, I know blades that have a curve or belly can definitely do this. How much of a difference it makes may be semantics, but it's a nice idea.