Regardless of where you grew it, carried it, sold it, or used it. It is still in violation of Federal Law, which has precedence over any state law. Remember Arizona trying to enforce the immigration laws? It's almost the same thing. The state law they tried to enforce ran into blockades from the Federal laws. Besides, what bank will provide financing to a retail store that is selling an illegal product? They have to worry about laundering money from drug cartels as it is. Recieving money from weed stores is just too easy for the Feds to find you and arrest the bank managers, employees, and store owners.