There isn't much else. Depending on the mainstream language in question you may have a little bit stricter typing, and while you get Data Race protection that is motivated by wanting to get performance from multi-threading with less risk.
Writing a low latency, high throughput ad server / RTB system from scratch? Sure, go Rust. Google uses C++ for this stuff still for a reason.
But in reality most of the services we're talking about are I/O bound low-thread-count data pipelines. And they'll be perfectly served by various managed languages.
Instead we get tokio-all-the-things...And Rust is a flavour of the month, and the JVM Isn't Cool, etc...
* Immutability by default, including a warning for unnecessary mutability
* Usable documentation even when the library author wrote none
* Extremely low-friction testing, including fuzzing
To name a few.
Racing to get an HTTP service that starts but doesn't do anything you want it to do correctly isn't really useful; in my experience, that's the only advantage e.g. Python, Go, etc really give you over Rust.
And honestly, TypeScript's union & intersection types are pretty nice and that language is nice and expressive.
Actually I actually routinely run up against expressiveness limits in Rust's enums in places where e.g. Scala would actually allow for a more static-declarative model (for better or for worse). I haven't worked in Scala in 15 years, but it was actually quite compelling.
It is such pain compared to Rust's enums. Wish there was more Rust front-end.