N exposure and N+x exposure for example;

N+x: (dMax - dMin) < N: (dMax - dMin)

N+x has a denser negative, but a thinner image (on the negative), the image density range is maximum minus minimum density, ie: black and white are closer together on the negative in terms of optical density.

Less gradiations on the negative (though still plenty unless it becomes severe)

Displaying min and max density at the same print reflectivity or RGB values requires the contrast to be stretched out, more than the N negative, grain is no longer noise once moving to a print or scan, as it is now part of the signal being used, and is treated the same - the grain contrast is increased too.