What makes bitcoin bitcoin is incompatible with central state control. This is to say that you can't centralize a concept that relies on decentralization as a premise and expect things to work out. A "government cryptocurrency" is just fiat by another name.
Well spoken. It's laughable that people still don't seem to fathom this. In /r/buttcoin, one of the primary arguments that Bitcoin will fail is that "ultimately banks will just launch their own cryptocurrency and back that one" as if that makes any sense.