I have little to add here that hasn't already been done. From most of what I have read or experienced, the idea of Chi is a tool used by martial arts teachers for those who need something spiritual to their martial arts.
I experienced it in my own Tae Kwondo classes. One girl could not for the life of her break a board. It's not hard. They're specifically sawed to be easy to break (with the grain). I was breaking boards at 4, but this girl was in her Mid-20s, and was under the impression that breaking them was hard. Master Park told her to "focus her energy", and "visualize her energy into her hands". Sure enough, she broke the board.
It was about a month after that I actually asked Master Park about the "energy". (He was really intimidating) He explained to me that he had never believed in "energy" (ki, chi, whatever), but it helped people believe in themselves.
It works in another form, as well. Imagine you are a top martial artist, and another martial artist does something in demonstration you cannot imagine possible. If he explains that it was because of some mysical force, you might think twice about attacking him.
Card tricks aren't magical or mysical either, but they still take us aback. As I say, "Chi" (Qi)" is a tool, not real or right, but it's there.
I take the middle ground on this one. If you tell someone to focus their chi, and it helps them advance, I have no problem with that. If you tell someone that they can leap from 10 stories using their chi, that's another thing, and I will argue against you to the end.
Another warning... A lot of Chi proponents point to Bruce Lee as a believer. He was not. He was very much a skeptic. He was disillusioned with the mysticim very early in his life. "I refer to my hands, feet and body as the tools of the trade. The hands and feet must be sharpened and improved daily to be efficient. It is true that the mental aspect of kung-fu is the desired end; however, to achieve this end, technical skill must come first."
He was one of the first martial artists to use cross training, (which made him effective), and was very critical of Shaolin tricks (breaking spears on the neck, etc.)
He also hated bullsh** claims. He looked at other "insta-awesome" martial arts schools. He said something to the effect of (not a quote, just a paraphrase) 'I have heard of the 90lb woman taking down the 200 lb mugger. My suggestion is to kick his groin and run as fast as your legs can carry you'.
Well, this turned out to be way longer than expected. Sorry if it was too long winded.
