The Cards may continue for the rest of the year to strand runners at the highest rate in the history of modern baseball by far for the rest of the year. That doesn't make it sustainable.
The Cardinals pitcher even if they do regress are still good. They aren't going to become Dan Haren. None of the Cards pitchers are as good as Cole. That is why, in a one game playoff, I would rather face the Cards.
Now if your talking about a 5 or 7 game series I would rather face the Pirates. Their rotation is top heavy with their 3/4 starters being subpar. I'd like the Cubs chances better their than the Cards who have 1-5 depth, but not an ace.