What are the applications (and limitations) of using chest hair for transplants?

[Centrino]

Seems like I've seen this practice referenced a number of times, but it seems like there are significant limitations. What and why?
If donor hair on the scalp is a precious resource because it is so limited, why not resort more often to supplementing with chest hair? Why isn't this standard practice?
For many people it seems like simply having some coverage/density, even if it needs to be regularly clipped short (like 1" - 1.5", because those hairs just don't grow longer than that), it'd be 1000% preferable to being bald.