The game key card does not have the game. It is a glorified link to a digital copy, which still needs the cartridge to launch instead of the convenience of a fully digital copy that you could open immediately. If the servers ever go down (which they inevitably will, they always do), a cartridge is still playable, and it will be playable so long as the materials last. A game key card will be lost unless you have a backup copy, just like digital. 

Game Key carts are essentially digital games you can resell, but with the extra annoyance of having to transport the plastic to play the game

Being fully on cart save space on the internal memory, but aside of that the issue is once the servers go down you will lose access to your games unless you download them and keep track on the files on SSDs


It's worse than digital if you don't want to resell your games, but better than digital if you want to resell them

When GCK is the option I will simply buy digital. Quicker, faster and more convenient 

You never explained the “What difference does it make?” part. I still don’t understand in what (meaningful) sense is a GCK any different than a game with the full game on cart. You can loan the game to others, the key card will almost certainly still be fully usable well after the servers go down, etc.

I have playstation 1 games that if I sell them now they worth 50-100 usd , in 15 years the switch 2 key cards will have zero value.

So Simple.

And you also must spend extra money to buy an addition hard drive that costs a lot. (100-200 usd)

This is one the worst analogies of seen in my entire time on this forum. That's not the issue at all. The issue with game key cards is they are just a digital code in cartridge form. It's not a physical game. Without an internet connection they are completely worthless. The only real plus side is that, unlike a code in box, you can sell/trade in a game key card.

I really wish Nintendo would have ditched the "Game Key Card"concept for a "Game Data Card". What do I mean that? Simply put, the game card version of an install disk. In order to provide a cheaper alternative for game publishers that would still gave the consumer a true phyical game, Nintendo would swap the faster more expensive flash memory of standard Switch 2 game cards for cheap slower memory. Publishers would get a cheaper game card option and consumers still would get an actual phyical game. Standard game cards would still be preferrable but at least these "Game Data Cards" would a less anti-consumer alternative. 

If I get a regular cartridge for my Switch after the servers go down, I can still play the game. Maybe I don't get all the updates, but I still have a playable version.

If I get a game key kart for the Switch 2 after the servers go down, I have nothing but a piece of plastic.

When the game is on cart they are playable as long you have the console, no matter whether the digital storefront is up or down

Imagine you have a DVD, as long you have the player you can forever watch your movie. But it's different if you buy them on YouTube or Google Play, because once the store closes you will will have your to watch license revoked 

The GCK works like if you purchased something digitally, but the license is not tied to your account meaning you can resell them, but you still need the service to be open to play your games 

I think there are two groups of people this bothers a lot: 

1. Collectors who like to have game collections that work decades after release. 

2. People with slow internet. 

GKC are best for people who like to resell their games and don't go digital because of that. I think they solved a real issue with digital that many regular, non-ethusiast gamers had. 

I personally have gone digital for third parties and physical for Nintendo this generation. Why? I don't resell my games much these days, but if I do plan to resell Nintendo games retain their value really well. 

It is obvious why Nintendo doesn't require third parties to have real card versions for all of their games. It would reduce their third party support, even if the real physical carts had a price hike. I suppose Nintendo could subsidize the cards, but why would they do that? 

A physical object will degrade, true. But when it's in my possession, its rate of degradation is up to me, and I take immaculate care of all my stuff. For instance, I have an Atari-2600 and a slew of carts. Some of them are pushing a half-century old. They all work. Flawlessly. My NES carts all work, my Gameboy carts all work, my SNES carts all work, my Genesis carts all work, my PS1, PS2, Gamecube discs all work. The memory cards work, the consoles work. All of it works. Some of that is just a testament to their durability, but a lot of it is due to the fact that they're stored properly and handled with care. In other words, I am in total control over it, and that brings me comfort. I know that when I reach for my Megaman 3 cart and pop it in, it'll just work. And it won't have input lag, it won't have changes to the sprites, or altered music due to licensing issues. It won't look different or play different and be stuck inside of a HDD. It's as it was when released, as it was when I first experienced it. Static, pristine and virgin... for the rest of my life.

These are just some of the reasons I love ownership.

Guys Nintendo wants you to not be able to sell the game after 15 years.
They profit money from cheaper cards + they can resell you the games from their digital store in 15 years for the Switch 4.
If they hadn't the handheld monopoly they would have the fate of Sega with consoles sales numbers like Wii U and Gamecube. :P