It would be gamification if you got a (meaningless) achievement for doing your homework or something like that.
Sorry, I wasn't aware that stickers were meaningful. Or the distinction between letter grades as opposed to a flat percentage that would be more accurate instead of conflating everything from 86 to 100% accuracy as the exact same. Please, enlighten me as to the grave import of these things.
This shit works because it encourages people to work slightly more to achieve the next plateau when they're close anyways. Doing an extra assignment to go from 85% to 86% isn't fucking worth it, unless it also means going from a 'B' to an 'A'. The reverse also applies (people will be even less motivated to make an effort if the grade won't change) but the grades are generally close enough together that a grade change is possible more often than not, and work has to be done to maintain the grade anyways (which works better with immediate feedback rather than finding out your overall grade after you're finished).