Always, the camera loved him. It wasn't primarily a matter of looks. They were fine, even distinguished, but a little off. Nor was it the outlandish costumes, which came and went. The theatrical and mime training he underwent before breaking through helped. He knew which gestures would communicate the most.
But even that's not all. Underneath the flash and the dramatics you could detect a very human warmth, a quality that's almost impossible to fake.
That's part of what he brought to his music too. Things could get weird and they could get dark, While Diamond Dogs is sketchy as a concept album, the one thing to understand about it is "bad→worse." But there was always a heart beating within, if sometimes an angsty one. That may have been the secret to his success, and it's definitely worth remembering.