(not to mention physical media is usually cheaper, you can loan them, sell them, servers are never down for maintenance, etc.)
You don't have to rip the disk in order to use it in different devices, especially devices that can't physically take the physical media.
Good luck passing an actual bluray on your tablet using physical media etc. Possible to do, technically, but a total faff.
But this way, load the code into the locker and it "just works". And you still have your physical disk. Win win.