Milling allows both professionals and hobbyists alike to shape harder materials, particularly metals, into more complex forms than simple heating and bending achieves. Most intricate parts of larger machines saw milling at one point in their existence.
This doesn't make milling the sole purview of industrial level automation though. Just as the process can craft parts, the process is also usable to add designs to metals. With the right machines and equipment, metal needn't mean sacrificing aesthetics for function on a given project.