i think the reason nintendo went with cartrages for the n64 instead of cds was based on the fact that cartrages would probobly be harder to copy and/or emulate
Nintendo actually went to cartridges because they could sell them at higher prices. I think that cartridges are harder to make roms from, but they are also smaller in filesize making them easier to distribute. It wouldn't make it any harder to emulate. With CDs you have to have to emulate the cd drive using your current one.