state wants to get tax. the input and output of the money can not be controlled. also a serious competitor for bankers. also a good way to make money. countries are opposed to it. a money they can not control is troubling governments.
Different government have different opinions about cryptocurrency agenda. Many government not satisfied cryptocurrency presence in their country and ban it in their country. The main reason behind this its cryptocurrency decentralised nature. Because of this nature it does not under control of any government rules and regulations and bitcoin also affect an country national currency and affects national banks profit and progress too. And these two above thing ultimately affects their country economy growth.