very interesting and controversial topic. First and foremost, most people do not fully understand the block system and they think that it makes the crypto currency "Neo" from the movie "The Matrix" - something like a liberator. But there is another side to these technologies. As you wrote, the government can control the growth of their prices, and there is likelihood, under certain circumstances - a big brother will know everything about you.
The negative side can be announced that due to block technology, "dirty" cases can be financed.
Thank you, interesting article