OP, either you're trying to teach or ask questions; your post didn't make it clear as to what you're driving at. It sounds like you posted in a hurry.
~snipped~
Do you really buy money or you mean investing money to increase income and I think that is how it goes.
People can actually buy money. Buying other currency pairs with one's own local currency isn't that buying money? To make it look fanciful, they call it currency exchange. What about when someone exchanges their own local currency with the same local currency pair like what we have happening these past few days in Nigeria? Nigerians are withdrawing the same currency pair from POS and other channels that aren't the banks for higher rates.