Black & White- grainy portraiture

Normally in the world of photography we are mostly interested in creating images that are as sharp as possible. We purchase cameras with the most megapixels we can get for our buck. Back in film days, we would use film with the lowest ISO number possible given the lighting conditions in order to avoid grainy images. Now with digital photography of course we can change the ISO whenever we darn well please. But sometimes, grain can be good. Desired. Wanted. That's why increasing grain in Photoshop is an option. Here are a couple grainy b&w images of my little Alex when he was just pulling himself up. Shot using natural window light.