2020 will be the year when more governments are going to be including blockchain in their systems to become more transparent and more reliable in order to offer a better service to their citizens.
Why is it that you decided that countries should make their national digital currency on a transparent blockchain? In most states, corruption thrives, which is beneficial to the governments. A transparent blockchain will simply not allow corrupt activities.
I think this wont really happen. In fact lot of government in different countries denied accepting bitcoin as a currency because it was s decentralized one which they cant control its value so how you came up with this idea.
Only as a government that accepts bitcoin in its country and even then cannot control the value of bitcoin because it is decentralized so it is difficult to control and the government only legalizes it.
Still, I have read the news that this year many governments will adopt the blockchain but that is not a complete control, but only applying the blockchain system in the government so that it will be widely known and popular again in this year.