For me personally, I'm studying other languages, and a good tool for effectively learning a new language is immersion. One tool I wanted to experiment with was taking something I'm familiar with, for instance Pokemon Moon, and having it installed in both English (for regular play) and Japanese, Korean, or whatever other language. Each regions' game cart has the exact same ROM on it, I have purchased the game from multiple regions and attempted to dump them but they just result in the same file.
The language itself is determined purely by which one you pick from the menu before you start the game, and as the game only allows one save, the only way I was able to find to do this outside of editing my ROMs was save-juggling with checkpoint, which is a hassle and gets confusing if I haven't used it in a while.
I realize this is a fringe usecase, but this is what I was looking for it for.
EDIT: to clarify, when I say they resulted in the same file, I don't mean the same file name. They're exactly the same ROM in every way, the only difference is the sticker on the plastic.