Why, then, use reverse at all, you may ask. Simple. $$$
Less work for the brakes means brakesets last longer, and brakesets cost big money. Idle reverse makes no more noise than no reverse which is why many airlines use idle only - saves dosh, saves wear and tear with no noise penalty, = win win for a change!
If you really want to save money then don't use reverse at all, just brakes.
It costs a lot more in maintenance to service reversers then it does brakes.
However I do agree that if you are going to be using the reverser at all it does save on brakes.