Currently there are twenty one states that have legalized marijuana:
The total number of people who use marijuana medically is 1, 029, 315
Marijuana helps reduce chronic pain
Disadvantages to legalizing marijuana:
More serious abuse of the "drug"
Serious lung diseases (hairs on the lung disappear)
Some consider it a gateway drug
Bad influence on children
So, even though there are many benefits to legalizing marijuana for allowing it to be recreationally accepted or medically, there are also some disadvantages. I personally believe that it should be medically allowed everywhere, because there has never been a reported incident of anyone dying of overdosing on pot. However there has been on other pills, and drugs. SO in the long run, the biggest benefit to legalizing marijuana would be that the government could make money off the tax of the sales.