The short answer is that smoked or ingested POT is NOT a "medicine". Like alcohol whatever good it might do is far offset by the harm it does. The ONLY medicine that is derived from pot IS Marinol (and to be frank I'm not sure that they don't use synthetic THC for that). So there is no NEED for pot to make ANY medicine. So your question is moot and based on nothing but desire to pretend that pot is medicine.
So only the most effective drug for any given condition should be legal?
The short answer is that smoked or ingested POT is NOT a "medicine".
Still no answer to my question (in boldface above).