Rust has uses you haven't mentioned. For example, each compiled language from the ML lineage (and almost every language period) has its own runtime, particularly, its own assumptions and contracts about heap-allocated storage. In contrast, Rust famously does not need a runtime library -- and it is low-level enough that it can usually (with enough cognitive effort by programmers) interface with an arbitrary foreign runtime library -- so when the goal of the code to be written is to interface with code in a compiled language from the ML lineage, you usually have only 2 memory-safe options, namely, the same language as the code-to-be-interfaced-with and Rust.

The situation is a little more complicated than what I just wrote because two programs written in different ML-style languages could communicate via inter-process communication. But I don't see that. (Maybe my experience is not broad enough?) What I see is, e.g., Python libraries written in C and C++ (and Fortran, which is also not memory-safe) for performance reasons where the only memory-safe language that could have been used instead is Rust.