This is brilliant! It serves as a single source of truth, builds on first principles, and acts like a universal test case.
Just as each Wikipedia article is about one "thing", each Wikifunction performs one job. Once you know a Wikifunction works reliably, you know every other Wikifunction which depends on it can theoretically trust its output.
This project seems really exciting, especially in the context of AI. Very cool and I hope to see it flourish.