PAI - 16 bit images minimal effect

I’m scanning slides on a Nikon Coolscan 4000ed.

I’ve scanned a given image to 8 bit jpeg (hi quality) and 16 bit tiff (Nikon Coolscan 4000ED, Vuescan software.) I notice that using, for instance, the sharpen tool, it has minimum effect in the 16 bit image (hardly see any change), but the 8 bit image shows dramatic effect.

Any idea why this should be?

Suggests there is no advantage to scanning 16 bit images?