don't hold me to this, but IIRC the 4EAT would work the same way with the exception that the center diff is electronicly controlled. Power distribution from left to right would be the same as a manual, but front to back Should be more effecient I would hope. Isn't it basicly an electrical LSD rather than a mechanical LSD?
Edit: forgot about the question... yes, an auto would benefit just as much from a rear LSD as a manual. Would it benefit more.... I don't have a clue.