Physical cartridges are just as temporary as digital copies; unfortunately. This is starting to be a big deal with the 3DS. Nintendo doesn't use ROM; the carts

Physical cartridges are just as temporary as digital copies; unfortunately. This is starting to be a big deal with the 3DS. Nintendo doesn't use ROM; the carts start degrading after a decade or two. The console tries to automatically correct any data integrity errors, but if you aren't using them on a semi-regular basis they'll eventually fail. The 3DS homebrew community has built some tools to attempt to recover failing carts, but for long term ownership your best bet is digital copies that can be backed up. Homebrew that enables dumping carts is also good, but who knows when that'll happen for new consoles.