One reason is new applications in legacy enterprises that are slow at adopting newer/better languages for a variety of reasons. I used to work as an embedded SWE for a Fortune 500 that made heavy use of C++ and was very resistant to Rust/Zig/others, but was much more willing to adopt newer versions of C++ for new projects. Although I would have preferred to work in Rust, having features like these would have been great in that environment.