it's for the same reason why you can use a tank on the desert or terrain...but you put it in a swamp and no use. make sense? you cannot crystallize a certain style and say it will dominate everything. you have to keep an open mind to all. that is why it's mma. that is why it's a ring sport. but if you come in there boxing and not know bjj and you get tackled to the ground. it's like swimming with the sharks, you'll get bit, one way or another.
"Combat Ki" is just Chinese Chi Gung. I've seen some of these demos and they look like they're taking full power shots to the jaw, throat and groin. Don't know how they do it, though the human body is capable of some crazy feats sometimes. It's also probably due to the mind over matter approach and the power of suggestion. If you believe you are indestructible then you won't feel any pain. Like the guy who keeps fighting despite being shot and stabbed numerous times. Course we don't know privately if these guys go home puking and peeing blood. For one, I'd like to see them take a hit when they aren't ready. Anyways, this is the wrong place to ask. Ask the guys who do Combat Ki.