I'm the CTO of Terrateam. For "why not rust", I have found the downsides of Rust not compelling enough to use it. We don't need close-to-metal performance. We don't really need the borrow checker, a GC is fine. We are immutable by default so the borrow checker doesn't help much there.
Great choice by way, I feel too many reach out for Rust, because they lack the perspective ML type systems are not something introduced by Rust, rather a long linage of languages since ML/Standard ML.
Plus, OCaml kept the SML tradition in its robust module system, with modules as first-class citizens and ML-style functors, this is something hard to see nowadays, even among ML-inspired languages.
The sense I get from some comments is that if you need a type system and to compile to an executable, Rust is the only option, otherwise you can use pretty much anything. But, as you say, MLs have been compiling to binaries for decades. One of the first online books on OCaml is for systems programming.
I know that isn't everyone's view, but I do hope posts like this, even if not technicaly deep, at least let people know that there are lots of options out there.
