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 ?
Again it is because there is no such a global United worldwide government that can choose for every country what to do, so every country need to make there own research and decisions about cryptocurrencies attitude.