There were stones than shells and then coins and than banknotes and than money backed by coins and than FIAT money
now you have BITCOINS and FIAT cryptocurrencies and
NO-FIAT but backed with something more or less usable or trade able in real world so you have
asset cryptocurrencies
WHAT will be next depends on technology ... maybe some kind of virtual patterns with pieces of skills or memories or personalities transferable [ some people working on brain interfaces ]
so chill for next 20-30 years this is cryptocurrencies round in history of economy.