A key role of moneychangers was to help : Merchants from different places exchange one type of coin to another. Back then, moneychanger usually exist in every harbour of every cities. Traders from foreign country came to money changers to acquire the local coin (which back then is a form of currency) to do their businesses in that country
If you wanted to be a dairy farmer, I’d suggest working in the country. If you’re making a milk company or something, you could do it in either the city or country.
