Of course, I see your point. It's always in our interest to get money back for our work. But if minnows get the option to cash out immediately after they get rewarded, someone may decide that the more accounts he has posting content from, the higher the chance of getting noticed and receiving cash from a whale.
It's better to give more power to trusted accounts - maybe that's another use for the reputation meter - the higher your reputation, the more SD versus SP you can receive?
Regardless of SD to SP ratio, my idea would give everyone a much better chance to get noticed and receive money for their work, right?