Actually it may be a factor now. Since bitcoin is known for its anonymity, maybe the government is actually using it know. but then again. corruption is not really about what currency the government is using but corruption depends on the actual character and moral of the people who runs the government whether they are honest in running the nation's money or not.
I would go a bit farther... Corruption depends on the actual character and moral of the people who votes on the politics that run the country. A corrupt government is the reflex of a corrupt people. What Bitcoin can do, is to give honest people the opportunity to live "out of the system", so they don't need to fund the corrupt system where they live, because they don't need necessarily to use the country's official currency anymore and don't need to pay part of the taxes these corrupts use in their own benefit and in benefit of their minions.