Because of anonymity, there are some countries that ban bitcoin because they cannot track the inflow and outflow of cash and cash equivalents so it would be hard for them to know if the people in their country are doing something illegal or not. Because it is decentralize, it is hard to keep track of the people who are involve with it which is not favorable for the government. Though there are some who are open to idea of accepting cryptocurrencies in their country, some just can't risk their financial status that may be compromise because of it.