I think you have a point, but the Brave Rewards program can also be seen as a redistribution system. For the sites that one wishes to support, one can choose to disable the ad-blocking system in Brave and see the standard ads. For the sites that are distributing bad advertisements, the ad-blocking system is useful and might be wise to enable. The in-browser ads then give a small funding to the user who sends it back to the sites that were unblocked, further increasing their revenue.