Bitcoin was recently called a combination of a bubble, a Ponzi scheme and an environmental disaster by one of the world's leading authorities on finance and economics. But underneath that sensational description, cryptocurrencies are saddled with underlying technological flaws that will likely prevent them from living up to the hype or merely becoming a more commonly used currency. Hyun Song Shin, head of research at the Bank for International Settlements in Switzerland, discusses the topic with Bloomberg News economics editor Scott Lanman.