Yeah, I think it's primarily for the button re-mapping. The option to update comes up when you go into the accessibility menu and choose button re-mapping in the newest dash preview from a few days back. I had just gotten done updating my controllers a few hours back. As far as I can tell, you can't currently re-map anything though.
The controller firmware updates are hard-line only.
New controllers can update wirelessly: https://support.xbox.com/en-CA/xbox-one/accessories/update-controller-for-stereo-headset-adapterThe controller firmware updates are hard-line only.