Even in conventional 35-mm photography color balance, exposure adjustments, and contrast control are manipulated to produce a satisfactory image by the photo processor. Digital camera built-in exposure meters try to balance the image exposure to produce a medium value. This works well when the subject is a medium value - like skin tones. But if you are photographing a dark mineral like azurite, the camera will lighten the exposure in an attempt to yield a medium value, making the image overexposed. If you are shooting a bright white subject like okenite, the camera will attempt to darken the exposure to yield a medium value, making the image underexposed.
Similar problems occur with color balance.
This works well with a normal subject. But if the subject is a specimen of etched green prehnite with no brilliant highlights, the camera will not see any white highlight pixels in the image and think color correction is necessary. Lastly, images need to be adjusted because digital sensors may artificially enhance one particular color. This is common with 35-mm slide films too, Kodachrome has exaggerated reds, Fujichrome has exaggerated green, Ektachrome has subdued neutrals, etc. So the image may need adjusting to accurately represent the subject.