Carts, although "cartridges" isn't really accurate to say anymore since games would most likely come on flash-type memory cards as opposed to actual cartridges like the NES/SNES/N64 which had circuit boards, ROM chips and batteries for backup and were much more expensive to manufacture.
Nintendo could have 32GB or 64GB type cards mass-manufactured pretty cheaply, and the combination of no physical disc drive plus being able to store additional save/game data on the cards themselves as opposed to a large capacity HDD built into the console would also save on the manufacturing costs.
On top of that assuming the NX turns out to be a hybrid console / handheld device, being able to play the same game cards on both devices would be awesome.
On 2/24/13, MB1025 said:
You know I was always wondering why no one ever used the dollar sign for $ony, but then I realized they have no money so it would be pointless.