The payment system of bitcoin if totally free and anyone can invest or exchange bitcoin without using his/her real identity. That's the main problem why many countries banned bitcoin. Every country gets a big amount of money as vat fir each transaction of money. People have to give this money. As bitcoin is free transaction system, people are using this coin vastly. And for this the banks and the countries are at loss. As bitcoin system doesn't need any real identity of the user, the security issue for the country harms.