Comment by mock-possum

I don’t get why it matters what currency people use - all currency is exchangeable, isn’t it? What does it matter if you buy something for dollars or pounds or euros or yen?

If I’m buying 1 barrel of oil for $100, does it matter whether I convert my USD into 150 of this currency or 50 of that currency, according to the current exchange rate, before I pay? I still get 1 barrel of oil, and the seller still received an equivalent to $100 in exchange?