With that process you can also get spot colors that are not in the CYMK space, for instance last week I struggled with printing an image of Rudbeckia flowers until I understood that the RGB version of that yellow (at the edge of saturation so probably not as saturated as the real thing) doesn't exist in CYMK which means if you don't modify the color to be in gamut the printer will do it for you -- probably not the way you want.
With spot color (say Pantone) I could get some ink mixed up that would color match the flower even better -- it was before Pantone but Warhol's spot colors were often like that. And of course his work with the Amiga is much in the style he's famous for.