Have you ever loved a game so much that you purchased it on multiple platforms just to own? For instance, someone who really loves Final Fantasy IV might have the SNES version, PS1 version, GBA version, DS version, Wonderswan version, PSP version, sealed copies of all of these, versions from different regions, etc. and devote an entire shelf to all of them as an expression of how much the game means to them. It's the same principle here, except sometimes it comes off more as unhealthy obsession and a conspicuous display of wealth when otaku do it.
