Assuming that we had a magical supercomputer the games could be on, that anyone could access without taking the games from myself or others- wait, we have that. It's called emulation & ROMs.
Yes, it's a legal grey area... but it's so because companies don't want us to have infinite copies so they can make us buy the games again. In the magical scenario where we have moved past monetary value, the other big reason for ROMs becomes the driving force- preservation. Let's say 100 year from now, there is only 1 man with a working copy of Super Mario Bros. Nintendo got rid of the ROMs and all the other carts/discs/etc have decayed. If that man will not allow the ROM to be dumped, because he wants to have the famous rare Mario game- then it's as good as lost. Eventually something will happen to render that game unplayable, and a keystone of gaming history has vanished forever.
As a general rule, I support ROM dumps & emulation, despite the legal issues and despite not actively using them, because that is how we will preserve our favorite games for the future. When all the NESes and Ataris are nothing but rotting chips & broken plastic, it'll be the ROMs that show people why we played these games.