When it comes to legalese, the devil lies in the detail. Here's the issue (IMO) with it.
While it may be legal for you to have a backup of games that you bought, the law is silent on the way you can play said backup. It does not explicitly say that you can play the backup on a mig. As such, ninty could still argue on the grounds that the mig circumvents their protection and as such, is not a legal device for playing backups and ban a person for the use of the MIG.
Same goes for emulators. While the technical process of emulation is legal, other things that are needed to make said emulation possible may not be legal. Switch emulators require prod and title keys to function but they cannot be legally obtained without owning a switch and the game respectively. Unfortunately, too many people conflate the two and think that emulation being legal means piracy in itself is legal as well.
