Look in your wallet. Do you have three or more credit cards?  Why? Because the different cards are used for different purposes, and because they hold different amounts of value. Do you have dollar bills as well as coins?  Why? Because they have different values, and are used for different purposes. Do you use a checkbook?  Why? Because you don't want to keep all of your money in your pocket.  You want to have access to other amounts of money stored elsewhere. Do you do banking or pay your bills online?  Why? Because it is much more convenient to do so. Each function of money may use a certain type of currency.  Sure, you can pay your house payment with dimes, if you want, but it is not convenient. You can take dollar bills around to the gas company and the electric company and drive the cash to your credit card companies to pay off those bills, but it is not convenient. A check or online bill payment is more convenient. Similarly, GGCurrency users will find that they may use local currency for buying food at the farmer's coop, dollars when they shop in the city, and GGCurrency when they send money online.