Yes, and no. In theory, you could absolutely "back up" any physical media you have to prevent wear and tear to the disc, which is a completely legitimate use case. And it's not considered piracy because by buying that media, you purchased the legal rights to use it for personal viewing. However, if you ever gave a copy of that rip to another person (or gave that disc away to someone else without deleting your rips), you would be commiting piracy.

In fact, I believe that even viewing the media alongside another person is technically not allowed, although clearly that's not enforced unless you're doing some sort of public showing.