I really like the idea of this ranking system.
I also feel like there could be few ranked ladders: x belt to y, y belt to a belt and so on. Might be too much of a stretch as I'm not sure about development complexity, but I feel like this would give a fair chance for players of all capabilities to compete and win prizes in their own category. Prizes should scale accordingly with ladder so it should demotivate people from making alts and abusing the system to some extent.