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.
Corruption thrives only because the country has a weak government system, in many cases, their citizen does not participate and do not get organized. Transparent blockchain is good for the people, the point is to let people as a society to thrive, not governments! Governments are here to bring solutions not to block progress.