People collect video or digital art. What would be the difference in that case?

In that case, they can collect whatever they want. The unique or special value of owning it in your collection is effectively nothing since I can enjoy the full-fidelity version at no cost wherever I go. This is the inherent problem with "collecting" something that is digital and can be infinitely reproduced.

I collect things because they're unique. Things that exist everywhere in abundance are not interesting to me. I could collect Coke-a-Cola bottles, but that wouldn't be special; I'd just be hoarding a bunch of trash.