Marijuana causes a pronounced lack of violent tendencies, makes you hungry, and worst of all, it makes you giggle.
Side effects of a more serious nature are that marijuana can be a replacement for tobacco, alcohol, paper products, and textiles, causing depressed profits and even obsolescence in those industries.
But in its illegal state*, it is very profitable for the prison industry, dealers and drug smuggling gangs and cartels, as well as dirty politicians and law enforcement officers, to name but a few.
In its legal state, it could be very profitable to growers, crop inspectors, wholesalers, retailers, the tax payer, regular law enforcement officers**, and the US Treasury to name but a few.
*Its establishment requires basic intelligence and the ability to think outside your ticky-tacky little boxes to understand.
**The main danger for law enforcement is the violence caused by dealers and drug smuggling gangs and cartels.