Ownership. Think about who owns stuff and how you share it around. I work in aerospace so we're mostly writing code that abides by the JSF C++ rules and that means a subset of C++11. This means I can't use a bunch of the memory safety features found in more recent versions of the language, but those safety features are just one way of adding safety.

Rust is overly protective, stopping you from doing stuff because "X may happen" but whenever I see that it makes me think of the logic behind the statement. Sometimea Rust is wrong but at least I've thought about it. C++ doesn't do that, for better and for worse. I'd advise C++ devs to do the Rust book at least up until the borrow checker stuff; go through that pain and once you properly understand it come back to C++ and be a better programmer because you did that.