I remember my Gameboy used cartridges, as well. However, unlike floppy disks, which often are unreliable right out of the box these game not only cartridges work just fine, even after all these years, they also load instantly, unlike optical games, including those released at about the same time. To this day, I still prefer anything that doesn't leave the physical media exposed, as CD's can even take a minute amount of "abuse" before they become unreadable. And yet, people use these for long-term storage; I've had discs ruined within months of receiving them. Therefore, I've made it a habbit of backing everything up on a HARD DRIVE for long-term storage.
However, the idea of holding a petabyte in my hand still sounds cool. If that could only become practical, That'd be great.