This gives you an illusion of freedom, especially compared with DD where companies can actually actively enforce that EULA.
DRM is more than just a fancy term for copy protection schemes like Securom or Starforce.
Nintendo cartridges run off of the cartridge, they do not install onto the NES. With computer games on CD it installs itself onto your harddrive, all the information is right there on your computer, however the game decides to check to see if the disc is in the disc drive before starting the game, if it finds the disc it will start up, if it doesn't then it will not start up despite all the required information being present.
That's the difference. A NES cartridge is required to play the game (in the way intended by Nintendo, that is the game running off of the disc) but that is not how computer game works. The analog would be accurate if I didn't have to install a game from the disc onto my computer and I could just run it straight off of the disc.