“…Blau (2017) argues that Bitcoin is a currency rather than a speculative investment, whereas Yermack (2015) indicates that it does not fulfil the functions of money. Polasik, Piotrowska, Wisniewski, Kotkowski, and Lightfoot (2015) provide evidence that Bitcoin is a medium of exchange, even though its price volatility is extremely high as compared with U.S. equity indices (Baek & Elbeck, 2015). Polasik, Piotrowska, Wisniewski, Kotkowski, and Lightfoot (2015) provide evidence that Bitcoin is a medium of exchange, even though its price volatility is extremely high as compared with U.S. equity indices (Baek & Elbeck, 2015).…”