Analgesia. It's a terrific natural pain reliever, Queen Victoria chewed it to ease menstrual cramps. The oil is also the only known effective treatment for epileptic seizures (and Tourette's, and half a dozen other health issues that have a nervous tic as one of the symptoms). The juice is also efficacious in the treatment of Crohn's disease, it stimulates appetite in cancer patients undergoing chemotherapy as well as sufferers of anorexia, the pulp is good cattle feed, the fibre can be used either as a strong, lightweight building material or the create a fabric ten times harder wearing than the best denim ... It's actually a marvellous substance. It would never have been illegal had not DuPont spent zillions lobbying the government to outlaw it (given that hemp was the biggest competition against their nylon).
I don't use it myself (have tried it, my body got stoned while my head stayed clear - like being dumped up to my neck in concrete, strictly zero squared). I'm opposed to unlimited recreational use, not only does it impair one's faculties in a similar fashion to alcohol, it's also a huge demotivator - while under the influence, pot smokers don't want to do ANYTHING. And although it doesn't CAUSE them, it can exacerbate pre-existing mental health conditions like schizophrenia and paranoia - even if the user was previously unaware they had them, it can cause an underlying suppressed condition to manifest itself.
I am neither a dissenter nor an advocate, but I have used it a few times to alleviate incredible, crying on the floor sciatica pain. It left me immobile...literally. I didn't like that, but the pain was gone.