As with the hands and feet, the whole body is imprinted on the ears. The ear acupuncture needles I use are especially designed to use for ear points.
The points are especially good for things that are triggered by stress.
But to be honest, it is my belief that most of our ailments and conditions are related to the stresses that each of us carries. So it is important to release them so they do not accumulate and cause us harm.
Another reason to use ear acupuncture is that as the ears are close to and either side of the brain, the reflex points on the ears facilitate the calming of the brain and desensitizing the emotions.