Personally, I don't think there's a right or wrong answer to the OP's question, with the answer changing from person to person.
To me, thinking as a supporter of DRM free programs overall, I find CDs and DVDs to be fine as long as the programs in it don't have DRM. But Blu-Rays, as far as I know, are, in a sense, DRM'd, so I find them to be far from ideal.
In the sense of preservation, from what I read, the expected life spam of those plastic discs is about 25 years, but thankfully creating digital back ups is viable most of the time. Only problem are, again, discs whose programs have some form of DRM (like Blu-Ray movies, games with SecureROM, etc.).
And thinking as a physical media collector, I find them cool looking when displayed on a shelf, and some have cover arts, manuals, etc., that are also pretty nice.
And there's also nostalgia, since I've dealt with discs for far longer than I did with programs distributed 100% digitally.