Cryptocurrency is riding a wave of investor exuberance. Investors are lining up to put their money in crypto assets, as devotees insist Bitcoin, Ethereum, and even Dogecoin (and thousands of others) will be the currencies of the future. But it is still unclear how exactly that process will happen; coupled with the environmental impact of mining cryptocurrency, some investors have serious reservations about cryptocurrency supplanting the dollar as the currency of choice. This Barron's article explains.