Allow me to share my point of view. Even thought there are medical applications for the use of marijuana ,and yes, some people could really benefit from it's use medically speaking ,most bad-intented people will abuse this system and will lay their hands on that sweet little grass essence with no repercussion.
And this exploit will ultimately make the system unviable, faulty and stop,depriving assist from those that really need it. It's a good idea,but purely utopical, like true Marxism.
The best middle ground I would be ok with,is with it being under strict supervision, approval committe and with strong indications that would benefit the patient.