I, too, have a non-competitive nature, and would find the negative used of leaderboard that you have outlined here rather horrifying, particularly as a K-12 student. I found learning more about intrinsic learning motivations helpful in that regard. Although the rewards gained by being extrinsically motivated can also elicit positive internal feelings in the learner, their behavior is not motivated by it. I like to think that I genuinely enjoy the process of learning for its own sake. But, if I am provided with an additional perk of earning some cryptocurrency along the way, that would be okay too.