It's convenient for sure, but people from that level don't need Bitcoin to move black money from one country to another. They have other ways of doing so where they leave practically no trails behind. Bitcoin may seem as an anonymous currency tool that comes handy in some cases, but everything is stored in the blockchain for ever. No way to erase these trails.
you make 2 mistakes here.
1 gov is not so high level as most people emotionally want them to be.
2 gov is not one entity.
please watch this video about currency wars of Andreas Antonopolis..
https://www.youtube.com/watch?v=6ZCVQHtD2l4