Both the 2D and 3D here are vectors -- both the 2D lines and the 3D triangles are represented as a sequence of mathematical points which have to be "rasterized"

Both the 2D and 3D here are vectors -- both the 2D lines and the 3D triangles are represented as a sequence of mathematical points which have to be "rasterized". But, put simply, triangle rasterization is just a much easier problem than curve rasterization.