How does foreign exchange trading enrich the world apart from by making profits for traders?

I can see how shares and bonds help to raise investment money the market in foreign exchange seems to leave whole economies open to plunder so surely there must be a benefit?How does foreign exchange trading enrich the world apart from by making profits for traders?Free foreign exchange means that the value of assets will mark to market no matter what currency you use. You would not want to invest in a country where it was difficult to freely excusing the currency -- e.g. the Ruble back in Soviet days.