To clarify my objection is with this statement
> no one ever writes down numbers in the unit of radians, they already convert to half rotations or full rotations by scaling with pi
That statement is true only if you are talking about geometry, If you are working in any other domain the trigonometric functions operate on real numbers and have nothing to with rotations or angles and if I call sin(1) I expect to get back 0.7847 not 0