"PETG Paintable - no problem, although the paint solvents don't really melt into the PETG, nor is is necessary because of the excellent tooth adhesion where the paint permeates the porosity." - pitts8r
I'm finding other possible uses for the 3D printed surface texture too. The pattern formed by the Z layering is quite regular, and so can form the basis of a rather aggressive friction fit between parts with identical Z stepping. And the same pattern can act as a guide for coil windings, particularly those consisting of finer wire.