Bitcoin is looking more like a pyramid scheme every day since the recent launch of a US bitcoin exchange traded fund. ETFs have the potential to lure billions of dollars into bitcoin, allowing investors and speculators who got in at the bottom to get out at the top, before the pyramid collapses. This renders the case for official regulation of bitcoin and other cryptocurrencies, and the launch of central bank digital currencies such as China’s proposed digital yuan, all the more urgent and compelling, before too many people become casualties of the prospective collapse. Whatever the true provenance of this…