Balance billing isn't the only reason that this is a good thing to be publicly available. Hospitals have been playing a game with insurance companies for years. The how much is too much game. Lets say service X actually costs the hospital $100 dollars to perform. Even though many hospitals are supposed non-profits (funny how 7 of the top 10 most "profitable" hospitals in the US are non-profits) they determine, hey we're going to charge insurance $300 dollars for service X. Insurance company doesn't argue.... so next year, hospital decides to raise cost of service X to $500 dollars, and the insurance company doesn't argue. So the hospital goes, "Hey, wonder if they'll pay $1000!" and raises the cost of service X to $1000. Insurance company goes, no that's too much for that service, we'll pay you only $800. So the hospital decides, "fine, so they'll pay us $800, so lets keep it on the chargemaster as $1000 so we can continue to justify receiving 800 from the insurance companies and maybe some poor sucker with no insurance will be stuck paying us $1000 sometimes.
Hopefully being able to see the chargemaster and the ludicrous pricing that hospitals charge will open the eyes of the public to say enough is enough.