I personally find virtual film effects distracting.
Personally, I've seen old silent films projected from original filmstock, in a theater that considers itself a museum. It's different enough from a scan that I wouldn't want someone to try to "emulate" film for me. Otherwise, I might as well just find the film on bluray or streaming and watch it at home, with all the cleanup and pretty soundtracks that come with home releases.
That being said: Very old film is flammable and can only be projected in flameproof projection rooms. (If you've ever seen a "safety film only" sign, this is why.) Due to the fire risk, scanning the film might be the only practical option.
This can be emulated with a post processing effect.
>Film grain is substantially different than pixels.
The grain can be recorded at a high enough resolution that the human eye will be unable to tell the difference when it's being projected.