I suppose it depends on how one uses the button. For instance, I’ve been using it for subtle, smooth zooms while shooting videos. The Apple button is the best option for this purpose. The OB and Spigen buttons are okay, but not quite as smooth. The Supcase can’t be used for this at all; it’s simply not sensitive enough to avoid appearing jerky in videos. That’s been my experience, anyway.
That said, the best approach is to activate the zoom via the button and then control the zoom on the screen by dragging over the new slider that appears adjacent to the button. This allows for a wider continuous zoom range and the smoothest zooms.