This is a strange sentiment. I think 99/100 people who know rust would not categorize it as "for beginners"
The real-world fact is that Rust is, as of March 2020 at least, an entry-level systems programming language. It's used as a stepping stone by former PHP/Python/Go programmers, who are very intimidated by C++, to get into performance-oriented coding.
Nobody actually writing embedded or sensitive code (airplanes, nuclear power stations, etc.) is doing it in Rust.
The language is young and you don't certify a software solution every two days or don't rewrite your nuclear power station code every day.
Very experienced programmers switched to Rust because it makes it possible to build large scale industrial programs both efficient and reliable. They won't switch to C++ just because they think they're good enough to live dangerously.
(btw I work on plant control and yes I write parts in Rust)
This never happens in the real world; not unless the 'very experienced' bit is experience only in languages like PHP or Python.
It's true that not a lot of people are using Rust for embedded software. That's a much harder nut to crack because so many of the toolchains are proprietary (and embedded support in Rust is still missing quite a few things).
You kind of do if you ever want to work on anything other than pet personal one-man projects.
Also: I've used Rust at work. In fact, I learnt Rust because I was processing a lot of data at work, and needed a fast language to do so in a reasonable amount of time.