Why does Sacks think that phantom limb syndrome might be importantly beneficial to a patient who has lost a limb?

Sacks argues that phantom limb syndrome might help patients integrate their lives with a prosthetic limb. Sometimes patients will claim that their phantom limb hurts but when they gain use of an artificial limb, the affliction often disappears as the brain is able to believe that the condition of the artificial limb is the condition of the actual limb. So sensations are re-ordered with an artificial limb and the artificial limb can be integrated through the sensory area that was once used by the lost limb.