I'm placing a bet now that these "key cards" are going to be the access point for breaking into the Switch 2, or being the source for piracy. But it all depends on how they actually work.
If they are basically "hard dongles" then it could range from practically impossible to very difficult but possible. With a hard dongle scheme the "key cards" aren't just small amount of flash memory that contain something like a unique cryptographic token (as has been used before by Nintendo) for accessing their CDN to download the game. They would actually contain active cryptographic hardware like the type of dongle you see with high-end PC software. If it is implemented very well it can be literally like breaking into Fort Knox IRL, or, if there is a flaw in the implementation, then there is hope from a very narrow angle. It is possible to emulate this type of hardware, and if someone can decrypt and dump the contents of a keycard, it can be loaded onto this emulated cryptographic hardware. This method would also provide a huge advantage in that you don't even need to hack the console, all the heavy lifting is done by the emulated key card. If done correctly the Switch 2 won't be able to tell it isn't communicating with an authentic key card and to switch games you just have to switch out the key card it is emulating at any given moment. The problem with this is that if the same key card token tried to download from Nintendo's CDN at the same time, I guarantee it is an auto-ban for that cryptographic token, making the original and any copies worthless, and it is likely that any consoles using it would be banned because there would be no reason for two people to have the same token unless it was piracy since they are unique for each key card.
If they just contain flash memory that has a unique cryptographic token in it, so a "soft dongle", then that means that all the heavy lifting is done by cryptographic hardware inside the actual Switch 2. If this is true then it means that regardless of how well it is implemented some avenue to break into the system exists, we just need to wait for it to be found. However, this type of implementation can end up needing the owner to modify the hardware on the console to make exploiting the flaw possible, which sucks. But, it is also possible someone could find a software flaw rooted in the actual silicon, such as with the first version of the Switch 1, and then you can modify the software of the console without having to do anything to the hardware of the console itself. From that point it's basically the same scenario as the first version of the Switch 1 as far as exploiting it.
I guess we'll have to wait and see once someone get's their hands on an actual Switch 2 and a key card.
