Some things are meant to be enjoyed, not to last forever

Velvet is surprisingly resistant to cat scratches. I have a velvet cover on my leather couch, and my cat goes to town on it with his claws. I can usually “wipe away” the scratch marks, and they’ve never punctured through to the leather.

Depends on the cat. Cat hair on the other hand, I'd recommend a secondary surface for catching as much as possible.

It also depends on the cats that live there. We have an adopted cat for the last year and a half that was a street cat picked up from a larger City. He's very social, has zero personal boundaries, and will explore any horizontal surface that he can climb his way to. That said, he only scratches on things that we put out for him to scratch on. Granted, we have multiple scratching posts throughout the house, and other assorted cardboard scratchers available to him. But so far we haven't seen him consider the furniture.