It's useful if you want to purchase weed without there being a trail such as with a credit card. Cash is viable but a recent trip to denver shows a lot of places don't take it. The biggest negative of cash though is these places are making so much money a day it makes them a prime target for heists where with bitcoin it is more secure and less risk. I think the more it is understood they will adopt it to make their business easier and safer.
News 
Market Data 
Discover 
