I'm not speaking for Rust level performance. I'm using Rust nowadays, because it's generally doing a lot right, that other popular languages struggle with IMO.

Think about error handling. I think even Java is better here than C#. I think it's quite a mistake, not being required to add all possible exception types that a function can throw to the function signature.

Then the next thing, I really hate about almost every popular language is implicit null. To be really safe, you have to check every (non-primitive) variable for null before using it, otherwise you have a potential NullPointerException.

Then take pattern matching, this is a baked in feature of Rust from the beginning and it does this really well (exhaustive matching etc.). There's "basic" pattern matching in C#, but it just doesn't really feel right in the language, and is not even close in capability compared to Rusts.

All of this (and more) makes Rust the less error-prone language, which I can say with confidence after long experience with both of these languages (both > 5 years).

I'm honestly not sure why exactly C# was chosen for most of the games, but it's probably because it's relatively good to embed, is relatively strong-typed, while being somewhat performant (compared to something like python or other scripting languages).