Pythagoras works with real-world dimensions. It knows the real-world distance between points, the real-world radius of a curve, the real-world coordinates of points. The benefits are numerous. Do you have a drawing that was made in US feet, but now need to annotate in Meters? Simply change the preference settings, and there you go. Two mouse clicks is all it takes. Pythagoras does not require you to start doing a complicated rescaling of your drawing to perform such a simple task.