I still think the point stands though: zig's build system is nicer. Still bad IMHO as I despise build systems where you describe the build in the same language. Most of the time, it's much better to have a declarative rather than imperative build system. All in all, Ninja/Meson/Cargo/etc are much better in this regard.
(and yes, I think build.rs was a mistake, a necessary evil. Definitely not a feature)
One such example of "daily driving" is for gRPC, where the canonical way to generate the protobuf and gRPC bindings using Tonic+Prost is through build.rs. Another is C-to-Rust bindings, for all of those -sys crates.
Though I've also seen it used to circumvent limitations of Cargo, e.g. for invocations of dependent cargo build steps, etc. Overall, it's less common (or more robust?) than it used to be 5-ish years ago.