The prevent defense prevents you from winning. I think John Madden said that. ND using it last night was fine, because we were up by 24 points with five minutes left. I mean it didn't stop them from scoring at all, indeed it allowed them to score twice. But there was no way they could score three TD and three 2 point conversions with so little time. So we could afford to give up two TDs, thanks to the pernicious, or even actively, occasionally agonizingly self-destructive effects of the so-called prevent defense, and still come out with the win. And we didn't blow our big lead completely.
There are narrow circumstances when it might help, and the idea is to prevent a random big play for eighty yards or something. But I think there has to be way less time than five minutes for it to be a good idea. But we did win, even though we predictably gave up yards and TDs while employing it. And the onside kick certainly helped.