It is unlikely that people will actually return to barter and transfer physical goods such as gold all the time, because it is expensive. However, they can usually promise to transfer value later. Such transactions will mostly cancel out and the amount of actually transferred goods is greatly reduced.

What you end up with is informal system of money transfer such as https://en.wikipedia.org/wiki/Hawala

Such a system will emerge as soon as people are prohibited to pay directly to each other. Instead of paying cash to you, I will pay for you in restaurant.