I caught the same issue, from a slightly different angle. Using key caps with that much protrusion surface will render them unsanitary in a relatively short time due to dead skin deposits, which will cure and fill the ridges. It’s not great from a health point of view. From what I remember when I was doing 3D printing, an acetone cloud bath could help to achieve a more glossy, thus more sanitary finish.
Incidentally glossy finish on porcelain-ware for plates, bath tubes, toilet bowls and sinks are specifically for this reason — gloss is achieved when the surface is flat to a defect rate smaller than the wavelength of visible light, which also gives bacteria and organic matter very little to hold on to.