Interesting that Nintendo has a new class of product, a game-key card.
It's still a physical cartridge but there's no game on it.. you still have to download it. However rather than a use-once code like you'd get with a digital download and the game is permanently in your account this isn't tied to your account. You have to have the cartridge to run it. So you can borrow this from the library or lend it to a friend or sell it.
Not great, but it's better than a game key, I guess thanks Nintendo?