I've found so many visual and sound effects no longer in use in game files

I was browsing through game assets and I found out that all the files of sounds and images for things that are no longer in the game could still be used. E.x. the assets for Kindred's W heal are still there. What's more interesting some of the assets of one champion are used by another (which is not so weird but still, pretty interesting). I wonder, if something will ever be done to use such assets again, because I feel like it's such a waste to keep so nice things in the vault.