I can understand vinyl. I have some repeat copies of blink albums. One Dude Ranch is a HT splatter. I played the shit out of it and it wasn't the best pressing to begin with so i also bought the SRC deluxe edition of it since it sounds much much better. Same with the self titled; bought the SRC even though I had the MTTS pressing.
There could be numerous reasons for multiple copies: Frame and hang one, one to be played, one to keep for later for when the playable copy wears down and you can no longer find/buy the album.