Columbus was the first European to report that cocoa beans were used as currency in the New World. He saw this in what is now Nicaragua in the early 1500s, but he didn't invest in cocoa. He apparently had other things on his mind at the time. Possibly the deliciousness of chocolate.
In Aztec culture, 400 cocoa beans equaled one zontli, and 20 zontli or 8000 beans made up one Xiquipilli, so the conversion rate might have been difficult for Europeans to express. Hernando de Oviedo y Valdez wrote about the purchases he made with cocoa beans, though -- one rabbit could be had for four beans.
Hernando Cortez didn't care for chocolate, so he wasn't distracted from its value as currency. Having received a cocoa plantation as a gift from Montezuma, he set about making cocoa beans profitable for Spain.
Jesuit Pedro Martyre de Angleria admired the use of cocoa beans for currency, on the grounds that it discouraged avarice. Cocoa beans wouldn't keep their usefulness if they were kept out of circulation for long, so there was no point in hoarding them.
Cocoa beans didn't catch on as currency in other parts of the world, but they have kept their value as the source of chocolate. There's no point in hoarding chocolate, either, but it makes a great choice for fundraising.
