Practicality wise, this might be doable. I have known people who use recreational marijuana and the trouble of cash vs credit has always been an issue with them. Stores do not allow you to purchase with credit cards so many people are forced to do cash only. Unfortunately, not many people carry hundreds of dollars in their pocket or have the time and energy to constantly go to banks to withdraw money. Its both dangerous and unpractical to carry such wads of cash. Think about getting robbed or a cop pulling you over and asking what all this cash is. If such a card exists where you can upload credit card info, get green med coins and you can purchase directly with these coins, then it seems like you are on to something here. The milestones to look out for is the partnership / connection to distributors and stores that would like to use this concept. All in all, the project sounds very promising and I will be looking out for the pre-sale along with forthcoming events. Good luck.