On July 2nd, at the 2019 Asian Blockchain Summit, “Dr. Doom” Nouriel Roubini once again attacked the blockchain and cryptocurrency. The specific contents include: 1. The current bitcoin is the main body of the cryptocurrency, and the price is still half of its peak value; 2. Most of the major regulators in the current world are still in the “Do nothing” situation for the cryptocurrency, 80% of the Encrypted currencies are scams; 3. There are billions of people in the world who use digital cash, but not many people use digital currency. The slow transfer speed of cryptocurrencies such as bitcoin is unlikely to support the demand for large-scale payment applications. 4. For the public chain of deploying smart contracts such as Ethereum, many smart contracts have loopholes and can be modified at any time, which cannot be called “smart” contracts at all; 5. Regarding decentralized applications, there are more than DApps. 75% are gambling and Ponzi schemes, and there are almost no other applications; 6. None of the current 43 consensus mechanisms in the blockchain have really succeeded.