I could imagine a number of reasons including 1. Crypto currency has potential that outweighs it's threat. Being able to transfer funds to people in other part

I could imagine a number of reasons including 1. Crypto currency has potential that outweighs it's threat. Being able to transfer funds to people in other parts of the world is of interest to several government agencies. Perhaps crypto currency could help them do this better / more efficiently / whatever than today. 2. They will have to be extremely on top of the situation in order to be able to bring down a crypto currency. 3. Even if they kill one, three others will rise to take the place that it had. That being said, I guess they could just ban crypto currency and perhaps most people would comply and the ones that were angered couldn't do much else than to watch it crumble.