Yes that is a thing. The game cart basically acts as a digital key and you have to download the game. You also have to have the game cart in the system to play the downloaded game. Thankfully the boxes that have this are clearly labeled. One benefit of this is you can resell these games which you couldn’t previously do for any digital game. Not a fan of the practice and having plastic junk for what is essentially a digital game, though. Seems these virtual game carts are selling poorly so hopefully publishers will start using actual full games on carts going forward.

That wasn’t what I was referring to in my original comment, though.