> So why do they need Rust then? What advantages does it provide?

That Rust didn't prevent one error in one specific instance does not mean that Rust didn't prevent any errors across any instances. Nor does it mean that Cloudflare didn't benefit from Rust in some way(s) elsewhere.

For example, from one of Cloudflare's previous blogposts [0] (emphasis added):

> Oxy gives us a powerful combination of performance, safety, and flexibility. Built in Rust, it eliminates entire classes of bugs that plagued our Nginx/LuaJIT-based FL1, like memory safety issues and data races, while delivering C-level performance.

[0]: https://blog.cloudflare.com/20-percent-internet-upgrade/