> Startup got 10% faster on Linux but otherwise, barely anyone noticed.

Just that?

I was expecting more from that rewrite. Maybe Rust is not so worth it after all.

It was already written in a very performant language so no significant performance improvements should be expected.

The benefit of a rust rewrite is memory safety improvements, but currently they've just rewritten zig to unsafe rust so they don't have that either yet

I don't think their motivation was primarily user-visible stuff. They backed themselves into a corner by forking Zig, and also were fed up with fixing memory errors.

You wouldn't notice either of those if you were a user, unless you happened to hit one of those bugs.

The blog claims rust chosen mainly to address memory issues, which rust is a better language for. So, success would simply be less new memory errors / easier to patch old ones.