Cryptocurrencies mirror some of the most famous failed currency experiments throughout history, according to Nobel-winning economist Robert Shiller.
Enthusiasm around the thousands of existing cryptocurrencies, including bitcoin, remains strong despite warnings from investors such as Warren Buffett that they're worthless. That mania and attempts to launch new units of money have existed in different forms since the 1800s, Shiller said.
Shiller, best known for warning about the housing and dot-com bubbles, pointed to the early 19th century, when merchants tried to replace the gold standard with "time money." The "Cincinnati Time Store" for example sold merchandise in units of work and closed just three years after it launched. One hundred years later during the Great Depression, economist John Pease Norton proposed a dollar by electricity, which also failed to catch on.