Well you already have a desktop so the added value is that once you get the content out of the disk you don't need them anymore. You can just store them if you want but not need to play with the physical thing, neither DVD nor player.
I mean if you particularly enjoy very specific things, e.g. bonus, or the physical feeling of the media (why not, harder to justify than with e.g. vinyl but still fine) you can still do that but otherwise the physical media isn't actually needed anymore.