As the price of Bitcoin has been sliding recently, trading near $11,670 after topping out at $19,343 December 16, Steven Englander scratches his head. With charges that suspicious trades are linked to price movements and general concern that a cryptocurrency crash could infect hard asset financial markets, Englander, the head of research and strategy at New York-based Rafiki Capital, kicks around value proposition questions that cut to the heart of the cryptocurrency movement.