It's actually what most adults do.....get the chores done then relax and do something nice. That's if they can find an end to the chores.
They end?
Actually, the better way to think about reward systems, whether natural ones like ndw is using, or more staged ones, is as scaffolding. We are trying to teach the kids how to delay gratification--that there are real life rewards to using your time efficiently. But at this age, even very high cognitive kids often don't have the executive functions to hold out for the whole bowl of candy later over a few pieces now. Reward systems are a way to give them an immediate small reward for delaying the bigger reward (have your cake and eat it too!), and a way to support the process of gradually extending the length of your delay prior to gratification. The eventual big reward is the ability to manage yourself and your environment in such a way as to attain life satisfaction (achieve your goals, become the kind of person you can respect, have a positive impact on the world, etc.). That's too abstract and too far away, so we create miniature intermediate rewards as stepping stones or frameworks to hold onto as we make our way there.