I don't think many people understand that inside those CIA or 3DSX files, there's a fairly unique data organization that you can't see unless you go to unpack them. Different developers organize their data in different ways, choose different packers for that data, and so on. I would think that people who mod PC games would understand this, but because they just have a game in one file, they seem to forget that's how things are done. I'm sure Nintendo has some dictates on this, but they can't make a universal data structure that works for all games so modding a game won't be a universal method either.