--You gain nothing.--
Wrong. With friction braking, the energy all goes to wasteful heat but with regenerative braking you recover much of the energy to use later to accelerate the car back up to speed.
That's a bit disingenuous to change the standard of comparison. I'm talking about terms of absolute use of energy. You've turned it into a comparison between friction brakes and regenerative EMF recovery of energy. Apples and oranges. You still have a net loss relative to the initial energy input to move the car. The losses are reduced, but not eliminated.