Bankruptcy at this point is just a way to signal to creditors not to lend more money to this individual. As you said alimony, child support, student loans, restitution are a must so the filing simply is a formal notice that "every penny this person ever earns is already earmarked, heed this warning before lending"

It's quite convenient though that it actually discharges the kind of debts rich people and businesses are more likely to accrue, while not discharging the kind of debts the middle/lower classes are likely to accrue when they're unable to pay them.