This skeutomorph litmus test mentality is a fad. Skeutomorph free interfaces have been around for a long time. Some really interesting programs have had them

This skeutomorph litmus test mentality is a fad. Skeutomorph free interfaces have been around for a long time. Some really interesting programs have had them (Ableton Live and Osc music control interfaces come to mind) but they haven't proven to be a decisive advantage or even had a radical effect on user sentiment where they've been applied. In music software, the impossibly skeutomorphic Reason (you literally connect dangly patch cables to connect audio effects) is thriving alongside Live and the consensus is that there's actually a place for the different styles.