In a program like this you can’t optimize for the assumption that every participant is acting in good faith and contributing good work even if it’s not accepted.

If a program incentivizes opening PRs even if they’re not accepted, the result will be a lot of maintainer spam from people opening useless PRs. This isn’t a personal hypothetical, it’s what we observe any time programs try to incentivize open source work. See the Hacktoberfest drama of years past where the promise of a T-shirt led to spam PRs across GitHub https://joel.net/how-one-guy-ruined-hacktoberfest2020-drama