I'm wondering this because is such a real threat to bank system and we all know how banks and governments are tightly linked !
BTC could make people more autonomous, self-resilient, being their own bank. You can use it like cash, making your transaction almost untraceable (or untraceable using e.g. monero or dash or laundry systems) : this is governments worst nightmare, isn't it ?
On that perspectives, banks is the main factors on how we can exchange virtual money to a real money so that's the main point in some of the governments allow BTC to transact on selected banks. It much wiser to used a virtual money than the real money.