You have missed the point of what Barnwell is saying. He is saying that tactical calling of plays to trade expected point value against variance do not make sen

You have missed the point of what Barnwell is saying. He is saying that tactical calling of plays to trade expected point value against variance do not make sense in the first half, because you don't know how close it's going to be. To illustrate: in an infinitely long game, you always pick whatever gives you the highest expected value. In a game with one play left, you always pick the play with the highest probability to put you over the amount of points the opponent has, even if has a lower expected value than other plays. The quote is saying that the first half is more similar to playing an infinitely long game than a game with one play left.