Answer:
It represented an agreed-upon value
Step-by-step explanation:
People were able to agree a value on a certain coin, which helped people from different parts trade with each other due to their understanding. In addition, people didn't have to barter with specific people who needed that specific product which wasn't productive and could be hard for some people who didn't produce products constantly needed. It proved to be extremely useful and productive, it's one of the reasons why civilizations were able to develop and have effective and efficient trade within their civilization and with other civilization.