Bitcoin has posed itself as a very strong currency since its introduction and it has also been a major concern to the Government. Bitcoin came as an electronic peer to peer payment network that requires no middlemen to complete transactions. Only the users secure the system and no central authority. The major reasons why they are worried about bitcoin is the need for no central authority. There are also other reasons it is big contender to the Government and their traditional currencies.
The traditional currencies we use are backed by nothing but mere faith we have in the Government but bitcoin is what more. The Government exercises control over currencies as they like but bitcoin does not because anybody can tap into the wealth. Although there are lot of arguments that bitcoin fuels criminal activity, traditional currencies also do this better. These are just few of many reasons why Governments are afraid of bitcoin and cryptocurrencies existence.
Even though Governments are against bitcoin, there is nothing they can do about it. Bitcoin is here to stay and in the future, it has a potential to disrupt traditional banking and be very successful.