and thinking "why don't the marijuana growers just store their money in bitcoin?" Of course volatility is a big issue, but that can go both ways. Marijuana dealers saving profits in bitcoin in 2012 and before would have made even more in appreciation. Dealers doing so from 2014 would have lost some of their profits (in dollar terms)
Sure, but all those businesses will have to deal with large amounts of incoming cash, so they too will have an incentive to take bitcoin. The secondary businesses wouldn't even need to keep any bitcoin as they could use something like BitPay or Coinbase to immediately convert bitcoins to dollars.
But for the primary growers/dealers, having a way of storing their profits without the risk of robbery would be a huge benefit (and probably lower storage costs substantially)
would have lost some of their profits (in dollar terms)
No, not in "dollar terms," in "general purchasing power terms," there is not some parallel bitcoin economy where people can buy the things they need for bitcoin that doesn't take into account the bitcoin exchange rate with other currencies.
Not sure why this is downvoted. The vast, vast majority of businesses accepting bitcoin for goods themselves are immediately converting to USD(or whatever) to cover their own overhead. Their prices are tied to the USD.
Don't think it's really about gambling the profits as much as making sure there is a profit after everyone else is paid.