As far as I know, bitcoin can not control the economy because it is not stable and what time it can fall. But it can help a country by giving job to jobless people. Whether they are in their home and using the internet, they can develop or make money. And another can also help by transacting money worldwide at no charge or transaction fee. Lastly, you can also apply a tax on it or bitcoin. It will help a country in terms of sufficient budget for projects that can be implemented by a country.