The government and the Central Banks are the worst enemies of bitcoins . Even though , many countries has legalised bitcoins but still no country wants to accept it as a primary form of currency because no country wants the loss of their currency and funds.
Bitcoins gives threat to Central Banks because bitcoins are purely decentralized and backs has no control over them .The popularity and legality of bitcoins will lead to a huge loss for the Central Banks and they will never let that happen. Bitcoin is a threat to the cliche form of finances.