What would reward be useful for if not to trade it for scarce goods? Literally there are only so many miles of coastline, so many front-row tickets to the Super Bowl, so many square feet of land within a 5 minute walk of any given place on Earth, etc.

At some point, that reward is going to be traded for something else that's in demand and where the demand exceeds the supply. If you interpret that as "use their extra earned money against the rest of us", then it seems that you are going to have to disallow the notion of rewarding those who decide to work more than average.