In my mind, small businesses will not be problematic to accept cryptocurrencies, but the main reason that there doesn't that is a restriction from the government side. The government can't control the flow of crypto money, so they can't know all the information about you and your money. Is this make sense for them? Definitely not. For instance, with bank transactions, government can get any transaction and follow where are from this money. The good advantage for government system to collaborate only with banks.