Are these cutscenes? If they wanted to make an effort to make the game work for offline play, they could just provide lower quality (say 720p) videos on the BluRay, and let the player know that if they have an Internet connection with no bandwith caps, the game would stream these videos in glorious 4K from their servers. And if the player has the disk space, the game could also offer to store (or pre-download) those videos on their disk.

Then again, game cutscenes nowadays use their rendering engine, don't they...