Yeah, but auto_win doesn't give your army the care you would. Suppose you're playing Marian Rome, with nine cohorts and a first cohort (with Cunctator's mod). Play a battle and a house rule should be never to lose the First Cohort. The auto_win doesn't care about that. Or, suppose your General is a valiant, brave man, known to charge into the fray, like a madman screaming "Death! Death! Death!"... (okay, enough of RotK for me)
Anyway, take that example. auto_win uses, of course, will not respect that, and let your General sit around watching his troops win.
auto_win is handy, but if it was THE important battle it CTD'd in, then I'd play it again. Just for role-playing's sake.