Afaik HDMI hasn't been a bottleneck for movies in a long time. The 4k masters I had when I was working at a theater averaged around 100-200 megabits per second, which translated into movies that averaged around 200-300gb. Larger WORM (write-once, read-many) storage would potentially allow for master quality recordings to be produced for cinemaphiles.

While you might think there isn't enough demand for it, you might also not be aware that movies from back-catalogs come on hard drives. When your company has an outing to a movie theater where you all watch Elf together, that movie was likely originally on a hard drive (afaik only new releases get the luxury of being transferred via satellite). Instead of shipping spinning drives, they could ship data crystals (project silica) instead. This would have the side effect of potentially making the crystals reasonably priced for collectors and enthusiasts, allowing them to get the master quality version of their favorite movie(s).