Well the NES-style graphics (and probably sound) will make production quicker and keep costs down, which will result in higher profits. Keep in mind that this is sort of a risky release--it is tough to gauge the interest in a series whose core lineage has been done for over a decade. I think if MM9 is profitable enough, it will encourage Capcom (and other companies) to invest higher funds into these type of game revitalizations.
I personally love older technology (I was just cleaning up an Apple IIc earlier today and trying to find a compatible power supply) and find vintage gaming to have a special charm. I'm sure many game developers feel the same way, and this project will certainly be fun for them to work on.
I'm all for flash drive game saves, though.