Much akin to the Hacktoberfest debacle, manufactured incentives seem to hurt public spaces.
Very similar: some guy created a video and a lot of people submit useless PRs, except for a T-shirt instead of crypto.
EDIT: Except, Hacktoberfest ran since 2014 and there was never an issue before the video, which (unintentionally) brought it a lot more attention and gave a bad example of an “improvement”. Incentives can be good if designed and explained carefully.