Update thanks to thethatfox:
Physical game cards may also not actually contain the game:
Nintendo Switch 2 Game-Key Card Overview
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.
Update 2: There is probably a difference in Game-key cards and card that contain real game data. So we don’t know right now how often these game-key cards are used or if nintendo is using them.
Not even that, currently games for say, ps5 download some from the disk, some from online.
This Key-card fuckery means they can now lock the online downloaded portion of that game and now this can be used to prevent the second owner from downloading it with the same code
Publishers have boogiemanned Used Games for fucking decades and now they’re taking another swipe to kill them.