As a political science student with some knowledge of blockchain developments/projects - this was a pretty interesting thing to think about. Knowing politicians and the way governments work, it's unthinkable for them to put classified information/data and more confidential details on blockchain or use Bitcoin to facilitate systems/processes. Maybe they could use Bitcoin in their reserves but it'll mess up current fiat currencies and systems as well. Although China seems to have begun thinking about turning RMB into a cryptocurrency, but the Chinese government also has extremely strict regulations against virtual currencies. However, it seems to be that the nature of any government and the underlying principles of blockchain e.g. immutability, transparency etc. are incompatible to a larger extent. I can't imagine any government willing to do that!