Of all the things to nitpick, attacking technical consistency is the most laughable when it comes to Star Wars. This is a Sci Fi world where space ships maneuver like WW2 fighter planes, psychic dudes with laser swords take on entire armies of well armed soldiers with ease, and building a planet killing gun with magical space crystals is somehow a better way to kill planets than tractor beaming asteroids into them. Its not a hard science setting.
Having said that, one thing that has been consistently shown in the SW universe is that it is ludicrously easy to hack nearly anything. Droids are routinely overcoming all manner of security protocols in nearly every movie, even hacking each other at times. Given this, having a massive archive where none of the information is connected to any sort of computer network is actually one of the more plausible parts of the science in this movie. We do the same thing in the real world, today (see "Air Separation" in IT security) so in a world where any bargain bin droid can rape your top network security, having the important shit in giant thumb drives off the grid makes total sense.
Having said that, one thing that has been consistently shown in the SW universe is that it is ludicrously easy to hack nearly anything. Droids are routinely overcoming all manner of security protocols in nearly every movie, even hacking each other at times. Given this, having a massive archive where none of the information is connected to any sort of computer network is actually one of the more plausible parts of the science in this movie. We do the same thing in the real world, today (see "Air Separation" in IT security) so in a world where any bargain bin droid can rape your top network security, having the important shit in giant thumb drives off the grid makes total sense.