Bitcoin exchange-traded funds have been such a smashing success in the US that they now hold more than 1 million of the tokens, or about 5% of what currently exists. That’s in the same ballpark as the amounts that have long been frozen in the wallet of the market’s original whale: The cryptocurrency’s anonymous and enigmatic creator known as Satoshi Nakamoto.Another buyer of equal size potentially may arrive on the scene, as a Senate ally of Donald Trump’s pushes to pass a bill that would requir...