For one thing, the barter myth “makes it possible to imagine a world that is nothing more than a series of cold-blooded calculations,” writes Graeber in Debt. This view is quite common now, even when behavioral economists have made a convincing case that humans are much more complicated—and less rational—than classical economic models would suggest.
In a small economy where individuals specialize in trades, they may find the process of setting up a centralized currency and maintaining it an unnecessary burden in order to trade. One option may be to use a commodity to exchange value between parties that want to trade goods or services and this is why gold and silver have been useful forms of currency in many cultures and times. Another option may be to use a barter system to trade.