Another way it cuts crime dramatically: it neuters the drug cartels by removing at least half their market (plausibly a lot more, as their infrastructure including manufacturing would be eroded). That didn't seem to fall into your two examples.

At least 60,000 people were murdered by organized crime just in Felipe Calderon's six year term.

One more way: by legalizing and taxing it, there properly should be more money available for treatment, helping to eliminate dangerous lifestyles that often cross over into crime.