The first American flags were made out of hemp, as well as the first drafts of the Declaration of Independence. Hemp is one of the most useful crops out there and the only reason it's not legal is because of the slight visual similarities to Marijuana.
Hemp can be used to make paper, clothing, beauty products, plastic, canvas, fuel, insulation, and medicines as well as many other products. It only makes sense to make growing it easier.
Earlier in America's history, you could face jail time if you DIDN'T grow hemp. Now you can face jail time if you do.