The packaged deal of the Blu-ray is a lot nicer IMO than having separate files for the main feature, various extras, and featurettes. Not only that, but there's more to "global accessibility" than subtitles and dubs. If you're trying to get your great-grandma to watch this (and why not? the movies are about 40 years old), physical media is simply easier to conceptually handle for much of the low-tech crowd. Finally, on the videophile side, few people have calibrated their displays for RGB PC output, so, for those who haven't, the BT.709 output from a Blu-ray player is truly better (assuming the display is calibrated at all). Finally, it's not like having the Blu-ray means you don't get an MKV. And heck, even if it did, you could just open up the Blu-ray's main M2TS file in kodi, or vlc.