For instance, Fahrenheit is vastly superior to Celsius when trying to measure body temp or ambient air temp, because it has a larger range, and can be more precise without resorting to more significant digits. But if you want to boil or freeze water, at 1 atmosphere of pressure only of course, and the water is pure and has no salts in it, then…well…Celsius is the way to go! Never mind that no other substance has melting and boiling points that easy to remember. We should definitely choose our everyday temperature system based on the phase change points of water at standard atmospheric pressure.