When talking about resolution and detail from digital scans of film, I think people sometimes have a flawed perception of the situation.

It may be true that 35mm negative only has 4k equivalent in detail resolution, and even lower for prints, opticals, and smaller formats, but a higher digital resolution is required to retain every visible grain in the film to the fullest. When people say 4k is overkill for 16mm, that’s not really true, because the digital resolution still needs to hold the physical image of every grain that would be visible in a projection of the film.