“99.8% test compatibility on Linux x64 glibc. The Rust port is real.”
Bun started life as a Zig project and the Zig faithful sold the language as the future of systems programming. Two years later the Bun team is quietly rewriting the whole thing in Rust because the talent pool, tooling, and library ecosystem make it the only sane choice. Pick whichever language you want for your hobby compiler. For anything that ships, you go where the people are.