OneTime on 09 June 2020
Cut scenes used to be separate videos, but these days they are mostly just rendered in realtime with the game engine. There isn't any particular reason to not put a high quality movie on the disk (apart possibly from the size), but the modern theory is that having a consistent look is important for immersion, so the game engine graphics are preferred.
As to whether cut scenes as a thing are dying: we are in the age of "not restricted by technology", so it's kind of up to the game designers if they want to include them.
