We are one example of those people who are using bitcoin but still governments doesnt adopt and used it, simply because of its characteristic. Bitcoin is a volitile currency which means it change anytime and anymoment. The volatility of a currency has a big impact to economy of one country and thats also one reason why they aren't using.
Image, if we are the government are going to utilize the funds of the people for investment? Basically no, no government will try to invest the funds of the people to cryptocurrency and even to stocks, what the government don't want is the potential of cryptocurrency to change and turn the table of the national financial currency to digital in which they might have a problem in governance. In this regard, the taxes plays the biggest part here. Even me as a citizen doesn't really want that to happen, government needs us and we need government as well.