3DS does have an account system and is able to log in to an account that previously was used for a different 3DS, but only if that account has already been unlinked from the previous system. Unlinking is easy if the device still works, and absurdly inconvenient if it’s lost/broken. The latter requires contacting their customer service, which seems like an utterly insane requirement for what should be part of a standard login flow and also means that as a non-automated process a human has the ability to refuse, but in almost all cases (currently) it is generally possible to “legally get those games back”.

Wii, in contrast, doesn’t have that ability at all. There’s no account system there.

Cartridges and game discs don’t pass the “hammer test”. They also have a limited lifespan: disc rot exists and flash memory loses its data if unpowered for a long time.

Regardless whether the game is a physical copy or has any digital updates/DLC, true game preservation requires creating usable backups, which requires (for offline games) either properly DRM-free game releases or viable DRM circumvention. Which yes, doesn’t exist for Switch 2, and is outlawed by DMCA and similar laws in most other countries. Ability to create personal backups (and reasonably short copyright terms) should be a consumer right and those laws are a major problem, but both physical and digital game releases are equally terrible in this particular respect. Unless they’re DRM-free, and on consoles they never are.

In any case, this Pokémon rerelease is for original Switch, with no differences for Switch 2, so it’s entirely possible to dump a backup. Though there’s unlikely to be much meaningful difference between that and one made from the original release. Aside from the emulator code, but community-made emulators have better features; the only people likely to care about it are those who want to reverse-engineer Nintendo’s emulator for reasons like making tools compatible with its local wireless connection.