There are many more reasons than mentioned here, and I wrote then down somewhere in my notes, that are not mentioned in the following list yet (one of them is: easiest offline hardcopy distribution):
Optical discs have such an interesting science and have many advantages. I wish that the world would understand. Optical discs are NOT out of fashion.
Additionally, HD-DVD has also unique advantages:
Hopefully, world will soon see HVD. It could also be reversible (no matter from which side inserted into the disc drive) and one data layer on a multilayer disc can be sacrificed for labelflash. Optionally, LightScribe could label the disc from one side, which would disable reversible inserting.
Maybe, the LightScribe layer could be re-writeable. (LightScribe-RW).