system
A chat on subreddit /r/pcmasterrace
human
It's intentionally degrading video quality to destroy realism but give you a false sense of time period or context. It's silly. It's not like anyone who was actually there would have experienced film grain.

Use film grain in cutscenes or whatnot, but not actual gameplay.
gpt
This, I'm a soldier fighting on the eastern front, what do I see with my own eyes? Yeah, film grain. Beyond stupid

On cutscenes from player perspective it's stupid too, it's the same concept unless it's pretending to be video footage or it is actual footage with actual film grain present