Dualshock 4 V2 and USB: what?

I have both a Sixaxis DS4, first revision (one that came with the original PS4) and a DS4 V2 (the new one, with a light bar in the Trackpad), which I recently bought due to it being less expensive on Amazon.

The fact is, everywhere online I read that the new gamepad features "USB connection for data" which means that you can play with the cable plugged in the console and not only charge the controller, but also reduce input latency by sending controls via USB directly.

To me, this is confusing though: I could already use the V1 controller with my Raspberry Pi 2 (no Bluetooth radio) using a cable just fine, same goes for my PC with a driver (Bluetooth being turned off) and my phone (by USB OTG adaptor).

Which leads me to the question: what has actually changed for as far as USB is concerned in the new "V2" controller?

The USB connection for data is a new feature for the PS4. Both revisions of the controller can operate in USB-only mode when connected to other devices. Only the new version can do it when connected to a PS4.

You can enable it from Settings > Devices > Controllers > Communication Method.

I believe the new revision can pass audio through USB while the original could not, which is why the original DS4 isn't enabled for wired communication with the PS4.