I have had a Kindle for years and I have bought quite a few books on Kindle where I already own the paper books. The duplicates are firm favourites that I want to read over and over again, and are usually books that are particularly heavy in paper form such as the Lord of the Rings. My DH and DSs have Kindles as well and we have a family library set up on Amazon so everyone can access all the titles. I have just had the following conversation with DH...
Me: Can I take the George R. R. Martin books to the charity shop seeing as we have them all on Kindle?
DH: No, I want to keep them.
Me: Even though you're never going to read them again?
DH: Yes.
Me: Why?
DH: I don't know, I just want to keep them.
AIBU to want to give away these books that will never be read again?