The difference is that in our western world we have so many jobs that do not actively produce something. Working at a production line you can't take the product home and sell it to pay your bills. A farmer in the third world takes his corn and trades it against some water or wtv. We need money in our western world to be able to rate things. Since nobody knows how much you worked this month except your employer you get paid the corresponding amount of money which you can use to buy stuff. It's the only way a company can work since they won't pay out their product to the employees.