I believe it's used with the car app. If you invoke the car app, then tap on the screen with 3 fingers it will bring up this utility. It's the same thing as the google's search widget if you tap on the microphone. I don't know if one is better than the other.
I also thought there was a way to activate it from the lock screen by swiping from the top, but I cannot seem to get this gesture to work under ViperOne.