Embedded Rust in Production?

I recently finished a contract at a (very large game dev) company where some tools were written in Rust. The tools were a re-write of python scripts and added no new functionality but were slightly faster in Rust.

The reality was that these tools were unmaintainable by the rest of the company. Only the author "knew" Rust and it was hard to justify a new hire Rust developer to maintain this small set of tools.

The only reason these tools were written in Rust was because the dev wanted to learn Rust (a big but common mistake). I pointed out to the Technical Director that this was a big mistake and the teams had taken on a large amount of technical debt for no reason other than the ego of the wanna-be-rust-developer. Since I "knew" Rust he wanted me to maintain it. My advice was to go back to the Python scripts and I left.

While they should get wider buy-in first then if the choice is technically justified within reason, its perfectly appropriate (and normal) for devs to pick up new languages in this way when existing expertise is not available on staff. No competent dev will accept their skills atrophying due to overly rigid political/tech choices.

That's how skills are built, its always been thus in such environments, and thats ok.