I have positive approach for this topic,It is possible and government will adopt it may be not early but in future .Adopting crypto will be need of government.Its era Of modern smart technology and new generation sick of from old trends like traditional banking systems.Artificial Intelligence overtaking the corporate sectors why Because Artificial Intelligence more productive than manpower.
Cryptocuurency save our time and no need of any third party to make transaction locally or globally,This is reason business tycoons and investors attract from the crypto and use it in daily life.
I am sorry for contrasting what you have said but I dont think that the cryptocurrency will be adopted by the government because cryptocurrency's price in the market is not stable and needs a lot of improvement and besides there are a lot of things does the fiat can do but not the cryptocurrency coz as what I said it needs more improvement.
Governments only think about one thing and that is to keep and to increase their power over their citizens, they are not going to accept cryptocurrencies but not because of the reasons you state, they are not going to accept them because they are going to lose control of the population and their money if they do that and they will never do something like that unless they are completely forced to do it, and I think in the future instead of adoption we will see many governments banning cryptocurrencies but people will keep using cryptocurrencies despite the ban.