I wouldn't reccomend buying flashcards that come with a pre-prepped card. Those SD cards tend to die within a very small span of time. Sometimes within just a few days.
You can buy drm free games / music / ebooks, and if you keep backups of your data (like documents and family photos etc), then you shouldn't lose the game. but with a disk, your toddler could put it in the toaster and there goes your $60