The question then becomes is that the type of student you want to create? Any elementary school teacher who frequently rewards students with candy can tell you horror stories of what this sort of system leads to. Every task becomes a bargain of 'what will I get for doing this?' as opposed to building an innate desire to learn.

Education is broken, but going this route won't fix much. Fixing standardized tests, or scrapping them, along with eliminating things like the SAT would go a long ways is creating better learners, instead of better test takers.