H2h shows which of the teams was better when they faced each other, so it's a good way to decide who'll be placed higher in case of equal points.
But there is logic too in using the GD as the decisive factor, and I think it might be one of the steps in making serie A more attractive. Instead of completely giving up and wasting time after a team takes a 2:0 lead, it will be in team's interest to score more goals and have a better goal difference. That alone will make the matches more interesting. And when one of those 1:0 winning teams gets burned on goal difference, the next time they won't just stop thinking about attack once they take a small lead.
Then again, Liverpool will have the best attack and still might lose the league on GD, so scoring more goals isn't always equivalent to having the best GD.