I mix QiGong with other stuff and get excellent results, I don't know why Chunyi makes that statement.
www.higherbalance.com has a program called "High Guard" that when combined with QiGong I get efffects greater than when I do the programs separately.
Sometimes people are so identified with their chosen path that they won't look at anything else or even consider anything else and that's not the way nature is. Nature is expansive. Yin Yang energy moves both inward and outward and if you're not expanding your mind you're only moving inward all the time.
The one exercise where you move yi/yang energy up and down the front of you is amazing. In "High Guard" there's this one where you move both together up and down the spine and BOTH are amazing. There is no right or wrong but if I was identified with either or I would be shutting myself off from learning something new. Energy is electrical and will obey OUR commands, whatever they are. There is nothing it won't do so saying there is one way to do it, or someone is right and the other person is wrong is just a viewpoint. A viewpoint that I don't have.