It's unusual for a portrait not to show the subject's face. The traditional approach is a full or three quarter view, with the occasional profile thrown in for good measure. Obscuring part or all of the subject's face can be an effective way of emphasizing aspects of a person's features or character.
In the first image, I like the way Ernie's hand seems to lead your attention in toward his eyes. The steely gaze is the main feature of the picture for me. The lack of any visible face in the second makes it almost an abstract study in form. All the attention - both the artist and ours - focuses on his work. The strong vertical highlights of hair and hoodie drawstrings also focus attention on his hands, reminding us this is a man and not just an abstract composition.