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 ?
Other Government see the good side of bitcoin. They knew the threat of bitcoin in their country. That is why the Government set a regulation in bitcoin transaction to avoid money laundering and other things that could harm in their country. Other countries who ban bitcoin doesn't want their Government to take risk of legalizing or letting their fellowmen use bitcoin.