I totally agree that we should avoid exposing properties that aren't needed. This is currently used by the HTML5 tech to tell the player that it is using native controls.
https://github.com/heff/video-js/blob/feature/control-bar-fixes/src/js/media/html5.js#L149

Other tech developers would use this method if they prefer the native controls be used. e.g. for Vimeo, you can't hide the controls, so this would allow the Vimeo tech to tell the player that native controls will always be used.

Overall, the native controls situation took a while to wrap my brain around. The player can have an option set (e.g. 'nativeControlsForTouch') that suggests to the tech that native controls should be used, but the tech has to know whether or not it can support native controls and ultimately make the decision of whether or not native controls are used. So `usingNativeControls()` is the way that a tech can communicate to the player what is happening.

I'm open to alternative approaches.