The main difficulty for people with this, MS and chronic muscular skeletal disorders that self medicate (due to the illegality) is getting hold of good quality supplies and getting the dosage right.
For example, hypothetically speaking, had I attempted about 20 years ago to treat some of the symptoms of my emerging osteoarthritis with a small daily dose taken orally (mixed with yoghurt) I might have found it difficult to have got the dose right and ended somewhat stoned at times. Some folk might like this of course but I (had this not been a hypothetical situation) would not.
I agree, it should be legalised for medical use.
I would still have some concern about its affect on brain chemistry if used long term - having worked within the mental health system and seen first hand how it can adversely effect people - especially young people. This is why I think it should only be used under medical supervision.
Just my 2p's worth.