"Not entirely bullshit" treatments are my favourite kind of treatments -- far superior to the "mostly proven" treatments those quack doctors keep trying to force onto an unsuspecting public.
Doctors can, and do, prescribe medications for off-label uses even if there is no proof that they work. Using acupuncture for an off-label use is the same thing.
Acupuncture is FDA approved for the treatment of certain types of chronic pain (and, I believe, asthma). It's not entirely bullshit.