The difference between regular coffee and Americano is that Americano is made with hot water that is added to the espresso, transforming the shot into a less intense, but just as delicious cup of coffee.
Coffee is just made by running hot water through coffee grounds and not through use of an espresso machine.
Americanos are made using an Espresso machine in which the hot water is then added to the espresso, thus transforming the small, strong shot of espresso into a weaker, larger cup of coffee.
So the main difference between Americano and regular coffee is how strong it is and how it's made.
The Americano is less strong and more weak than a regular cup of coffee.
Americano coffee is a good coffee but I also like the stronger cup of coffee that is regular coffee.