From April, 2019

IMF: Crypto Currencies and Monetary Policy

Cryptocurrencies today do not do a good job at fulfilling the main functions of money. They may be favored by some for ideological, technological, or monetary policy reasons. The blockchain technology they use does have some important advantages in controlling for fraud and maintaining privacy. But they also open up avenues for tax evasion and criminal activity. (Jeffrey Banks, IMF, January 2019)

ADB: Bursting the Bitcoin Bubble: Assessing the Fundamental Value and Social Costs of Bitcoin

[T]he fundamental value of a bitcoin is equal to the miners’ equipment and electricity costs relative to their expected block reward and fees. While Bitcoin is a decentralized peer-to-peer network with no central authority, the mechanism for adjusting the level of difficulty encoded in its protocol amounts to inflexible system of supply management. Hence, demand shocks have an exaggerated effect on the price of the bitcoin and each adjustment in the level of difficulty of mining a bitcoin results in social welfare losses. (Andrea Podhorksy, ADB, March 2019)