I think the comments sometime ago from Harbaugh about the SEC being a bunch of "cheaters" played into Saban's decision to rub a little more salt in the wound at the end.That last TD was very un-Saban like. Normally he just takes a knee. I think he really doesn't like Harbaugh so he just added the last TD as a final middle finger to him.
Great win! auburn lost, uga will lose later and make it a great start to 2020.