Normal maps can be transformed to bump/height maps, so they could be used in Shapespark, after such transformation, even now.
However, the main issue is that currently roughness, metallic and bump maps influence only the dynamic lighting, based on the the light probe images, but do not influence the static baked lighting. To take full advantage of such maps we would need to extend lightmaps to include additional information about the direction of the stored light. Unfortunately this is a larger undertaking, which we won’t be able to do in the near future.