Yes. You could spend a lot of money and scan to the high degree of accuracy as you claim and you might even learn something from the exercise
It is true that you can figure where the edges are to a much higher degree of accuracy based on measurements of the whole object that find the arc shape and the shape of the surface that its tangent to. That is the correct way to reverse engineer the CAD surfaces that were used to create the metal casting.
The point of the story was that if you just measure points in a small area looking for the imaginary kink you were talking about you wonāt find it.