As major economies across the globe—including the U.S.—followed QE measures in the aftermaths of the 2008 financial crisis, a good portion of the QE money made its way into money market mutual funds as a haven. This migration of funds has led to interest rates remaining low for a long duration, and the diminishing of returns from money market funds.
Cryptocurrencies are systems that allow for the secure payments of online transactions that are denominated in terms of a virtual "token," representing ledger entries internal to the system itself. "Crypto" refers to the fact that various encryption algorithms and cryptographic techniques, such as elliptical curve encryption, public-private key pairs, and hashing functions, are employed.
The world then decided to have fixed exchange rates that resulted in the U.S. dollar being the primary reserve currency and that it would be the only currency backed by gold, this is known as the ‘Bretton Woods System’ and it happened in 1944 (I know you super excited to know that). In 1971 the U.S. declared that it would no longer exchange gold for U.S. dollars that were held in foreign reserves, this marked the end of the Bretton Woods System.
But while cryptocurrencies are more used for payment, its use as a means of speculation and a store of value dwarfs the payment aspects. Cryptocurrencies gave birth to an incredibly dynamic, fast-growing market for investors and speculators. Exchanges like Okcoin, Poloniex or shapeshift enables the trade of hundreds of cryptocurrencies. Their daily trade volume exceeds that of major European stock exchanges.