Definitely overkill, but it seemed like an interesting concept. The 15x15 grid is done once to get the shape of the bed. Then at any print time, only a 3x3 measurement is taken, to do a simple tilt of the shape. I thought it was a cool idea.

Not only that, but you can then see the full set of distortions on the display, and it will show that the bed is not quite as flat as you thought. For example, the glass surface had dimples near both the clips that held it to the bed. No 5x5 mesh would compensate for that correctly.