Looks like a gimmick to me. The on the newer trucks when the voltage regulator kicks off the whole alternator freewheels until it gets down to 12 volts again, that might free up some power. I can't see something that's not inline in the circuit doing anything but preventing voltage spikes.

On my truck I ran grounds from my - battery terminal to the alt bracket, the frame, and the firewall, all in 2 gauge. Good mod, my own take on the Big-3 mod. She started much easier at -60F, but if I go back to UAF this year I'm dumping the red top and switching to two solenoid isolated blue tops.