In other words, we can estimate the home court advantage based on the above distributions. This comes about because a win by the home team means only that the home team's score is greater than the road team's score. The answer gives you an estimate of the home court advantage. Actually, this is only mostly true. In other words, teams play up or down to their competition.
Every team does it to some degree and some definitely more than others.
What this means to the analogy in the previous paragraph is that if you pick points in the home and road point distribution with some correlation, you estimate the home court advantage a little better than if you pick the points randomly. The result of applying this method to last season's point distributions for the home and road teams is a predicted home court winning percentage of 0.587. The actual home court winning percentage was 0.597. We know the home court advantage, though. This isn't a prediction, but a confirmation that the method is accurate.