I think it goes back to the idea that we want a competitive market to exist. For a competitive market to exist, basically you have to have certain standards of information available about the product you're purchasing.
Primarily, the FAA publishes these kinds of statistics about airlines to better inform consumers, to better enable their choice, and to drive efficiency within the market itself. Minus this kind of information, effectively the only thing you're making a judgment on is the price and the date of travel. I don't think that's enough in an industry that has a variety of different parameters that travellers look to when they travel.
Collecting this information and making it publicly available will have the impact of improving airline performance as well as informing the customer and informing the department itself of trends in the industry.