I've heard from some of my colleagues at other companies that Rust has a significant negative impact on developer productivity compared to C++. This makes Rust great for, say, the Linux kernel, where the security and performance features are really needed and the maintainers don't give a rat's ass about how much time and effort it takes for contributors to get their features merged. On the other hand my current company already has significant challenges in the area of developer productivity, and it could very well be that requiring Rust for a new internal project would doom it from the start just for that reason.