How much more useful are ever higher pixel densities?

My suspicion is that we are transitioning from an era where we feel that we have to display every pixel in the sensor for acceptable quality to one in which we can choose how we use all those pixels for our particular purpose.

Although it's true that shot discipline has to be much stricter to obtain critical sharpness at 100%, it doesn't have to be that strict to obtain benefits when viewing at reduced resolutions - which is how many or even most pictures are viewed these days. I'm speaking primarily of image noise and sharpening quality.  Downrez a 16MP image to 4MP or even 2MP of a 1080P screen, and you accrue lower noise in the process, and more samples of transitions that can improve sharpening algorithm performance.  The image doesn't have to be critically sharp to do this.

The result is a photographic tool with broadened scope.  So long as the increased resolution doesn't compromise the potential of the underlying bulk semiconductor technology or exact too onerous of a penalty in storage and processing time, we gain versatility.  We can up the discipline and print every perfect pixel or handhold a better rendered snapshot.

Too nieve?