Rust may be a very good choice for systems programming. However, safety criticial software can also be written in other languages which don't need a borrow checker -- Ada and SPARK for instance, or even in C with verificatino tools (FramaC etc.). Most developers also don't need Rust's "feature" of not having a garbage collector since they are not involved in systems programming. As for me, what makes OCaml attractive is its functional nature combined with a very practical imperative syntax. There is no steep learning curve like in Rust, and OCaml's compilation speed is staggering.