While editing might give a decent tonal range the image might suffer from artefacts or digital noise, which looks like mottling.
There are issues with heavily underexposed shots, too. While editing might give a decent tonal range the image might suffer from artefacts or digital noise, which looks like mottling. It might seem ok but is not a good look. Some photographers like to expose so that the histogram has a right-sided bias but without the graph bleeding off to the far right. The preview image might look bright but the aim here is to get more information into the shadows so when they are lifted in editing there is less digital noise in evidence.