Instead of rare books, let us rare video games or computers. Let's say someone bought a rare version of a Ninentendo system (an early edition) and said, "You know what, I'm going to see what happens if I apply a larger and larger force to it. Let's see how long it stays intact."
Mind you, they did a 3-D scan of the system so you can digitally see it, but the physical copy no longer exists.
How many of you would raise a stink at destroying it?
If not Nintendo, pick something you like and go back to its earlier days where something is rare and someone wants to destroy it, just because.
One of the things people complain about the digital age is loss of information. Sure, these books "exist" in a digital form today, but what about in 50 years?
This is why physical books are still superior to digital. We can still read books/scrolls/clay tablets from centuries ago. It is doubtful the same will be said for digital books.