Do you mean to point out mistakes for others to laugh at?
I don't know if I even agree with it. Yet, its always brought up when discussing the Yankees chances.
I'm not saying there's nothing to it, but I'm very skeptical of some of that folk wisdom surrounding differences in playoff baseball vs regular season. Same teams, same parks, but now it's different?
Perhaps if the Nats have a killer #5 starter while other teams #5's are awful, and the Nats make the playoffs due to that competitive advantage, then I could see that that particular advantage is nulified by the playoff format to an extent. But most teams don't ride the success of their #5's to the playoffs, so I would tend to think this a bit insignificant.