It is much simpler, and many kind of post-processing can be done on it better too, and also you can compile the fonts per printer (DVI doesn't actually care about the font glyphs at all, and does not require that it is even a font glyph as is normally considered) as needed. If you have a printer that implements it, you could even do such things as cutting holes in pages, printing raised or engraved text, invisible ink, etc, without causing problems with software that does not support these things.