Codeine has side-effects, like bumming you up with constipation. Pot has no side-effects, as far as I can tell, as a life long toker. I've noticed codeine and mj works great for pain, and codeine alone I can't even detect a difference if I take it or not.
This licenced supplier bullshit is just to put money back into the pharmaceutical companies, because grows are practically free in comparison, and can be done very safely through education and proper grow units. All of their reasons for doing this can be countered.