It takes tax dollars to enforce keeping it illegal and to support folks in prison for growing and selling. It takes money out of the Mexican drug lords hands. It puts money in farmers hands for selling the buds and stalks which can be used as paper and clothing and textiles. The government could set up state stores and even tax it and use those dollars on education.
I was with the libertarian point of view up until that last line where the gov't gets to regulate and tax it.