Game-key cards are different from regular game cards, because they don’t contain the full game data. Instead, the game-key card is your “key” to downloading the full game to your system via the internet.
Pay a premium for a physical copy of your game, and the cartridge may not contain the actual game. Only on Nintendo Switch 2.
Not true. Switch licensing works the exact same way as Playstation licensing. All accounts on your “main” console can play the same digital game, even offline. Your account can play digital games on any console as long as it’s logged in and connected to the Internet.