Not very enlightening. The logic seems to go...
1.) If you have two of 11 symptoms we've defined as bad (including craving, withdrawal, and lack of control - this would seem to include just about everyone who uses marijuana or alcohol for that matter), you have marijuana use disorder. BTW, they never tell us what all 11 symptoms are.
2.) Marijauna Use Disorder is Bad and should be treated.
3.) Severity of the disorder is rated as mild, moderate, or severe depending on the number of symptoms met. - But they don't give you a breakdown of how many of their 6 million people fall into each category.
4.) People with this disorder often abuse other substances. - But they don't explicitly say that there's a cause and effect. It could be that MJ attract people who are prone to abusing substances (i.e. they are treating/medicating themselves for whatever physical or mental ailment they have).
Seems a bit biased without much actual substance.