We developers love so much to learn computer stuff that we want to do it even when we don't need to.
I worked on data science, computational science, some system engineering and embedded projects. I tried Rust on all of them but it was valuable only for the third.
In data science the focus is more on speed of development and as much as Rust is more enjoyable to use than C++, it doesn't match scripting languages (namely Python) for the flexibility you get, the easiness with which you can adapt to changes and the lack of a need to focus too much on machine-related details. This is the least suited field for Rust between the one I mentioned, in my view.
Computational science needs to focus on algorithms and formulas, Rust can hide them a bit too much under "unwrap"s "iter"s and so on. Plus still no stellar library support and (my) experience with other tools (namely C + OpenMP, Julia, C++, numpy...) made me feel using Rust for that was unnecessary and slower.
When you are designing systems, however, that's where Rust is a complete game changer. Honestly I don't think C++ can stand a chance in its current level. Everything, from the package system, to the borrow checker, to the safe threading model, makes you pity your C++ ancestors for how hard they thought this kind of programming had to be. Rust makes it orders of magnitude more approachable, saner, and with better results too.
Embedded... it's nice but honestly all the dark arts of unsafe Rust are not standardized so it doesn't feel as future-proof as C already.