Does a game key card cart have to be in the Switch to play the game or is it not needed after the game has been redeemed?
Like, is it an eshop game at that point or some sort of worst of both worlds situation?
My understanding is that the game is not tied to your account though, so this enables lending and selling your game.
The key card acts like any physical that has a complete overhaul post launch. The physical goes in, the game plays from internal storage. It contains no game data, and you have to download the full game from the server.
So, I have a hacked switch 1 and I can assure you that any game that has had a "complete overhaul post launch" still uses about 80% of the data on the cartridge. Or rather, it loads the entirety of the cartridge, and then every update to the game after that gets strapped on top of it to overwrite whichever sections of the game it needs to or adds new stuff.
So let's take animal crossing for example. If there were 2 major updates for Animal Crossing, youd have something akin to the following list of files:
Animal Crossing New Horizons.nsc [8 GiB] (the cartridge itself, if you dumped it - in this case we're referring to the actual cart itself here though)base.nsp [16 B] (some kind of token file for DLC attach points or something)184810dheincoiepn02.nsp [300 MiB] (patch 1)01849...ahd4819.nsp [24 MiB] (patch 2)The switch loads the entirety of the cartridge, then it loads the base patch over the top of it to hook into the right location, then it loads patch 1 over the top of that, then it loads patch 2 over the top of patch 1, base, and the cartridge. Theoretically you could delete the latest update file and still have a working downgraded game. No original data is lost.
That's not a complete overhaul, I'm talking about something like Fortnite from 8 years ago to now. That's no shared code left. That's not a game that came on cartridge, obviously, but Animal Crossing only got a few tweaks and some additional content. It isn't an example of what a key card represents.
Oh, second question, just out of curiosity: is there a copy of the Switch firmware on a game key card, like there was on Switch 1 carts (and probably Switch 2 carts also)?
The system update would come from the internet in this case as well.
This only helps in areas where internet is scarce or non existent. Even banned switches are allowed to download firmware updates even if everythint else is blocked (source: just did this myself recently)
As I understand it, the key card does need to be inserted to play the game. It's not just a redemption code, it's a key to download and play it.
Oh, gross, thank you for the answer, though.
It's meant to be just like a regular card, but you just have to download the game instead of it being on the card.