I think this is one of those things youre not really supposed to talk about. I'm with neuhauser on the benefits to the individual developing these energies, but what interests me as a student of acupuncture is how to use it externally....and what we're talking about, of course, is good old fasioned magic. You can actually find machines on the internet that are supposed to amplify the personal chi so your spells will cast further (see techno-shamanism)
What interests me is not sorcery but the healing arts and allowing energies to flow not as I want them to but as the Tao or nature of existence dictates. For the purposes of beginning/intermediate internal martial arts folks, I would say what the classics say--Store it in the Dan Tien until you need it to defend, heal, or sustain personal health and development.
Again, they say the dragon can bite...
I heard a story once about a friend who used his chi to keep a cat from dying. The cat was really sick and was on its way out. My friend then focused his mind on allowing his own chi to help sustain or save the life of the cat. He immediately noticed that the cat gained in vitality for a few minutes and may have even opened its eyes. Sadly, the cat passed on a while later. The next morning my friend awoke with no voice, and he couldnt speak for nearly two weeks!!! Hmmmm.......
humbly,
CSW