"Money is only good insofar as it can be traded for something else. Money in and of itself is just little scraps of paper with numbers and pictures printed on them. You cannot eat dollar bills. You cannot clothe yourself in Korean won. You cannot shelter yourself in Euro or live on Reals. They can be traded for something, yes, but in and of themselves they are not resources.
So, a nation that only exports and gets nothing but money in return is, indeed, made worse off. They send off their resources and get nothing but paper pictures back. However, if they send off goods/services and get other goods and services back, then they are made better off!
Exports are a cost; they are what we give up in order to import. Imports are the real benefits of trade.
In short, the purpose of trade is not to acquire more money but to acquire more wealth".
Fuente: Jon Murphy