>"I would like to have the guarantees that Rust provides". If the Rust ecosystem depends heavily on C/C++ libraries, then the system has the properties of the union of all the flaws and the properties of the language do not translate into a quality of the ecosystem.
Of course ideally you get rid of all C/C++, but that may not be feasible. Combining Rust with some C/C++ still adds the benefit of Rust safety to the new code you write. The contained C/C++ is like the unsafe section of Rust code, a place where you have to be more vigilant, but you're slowly constraining the space where these issues can arise. And you can iteratively only replace those parts that cause a lot of issues.
Of course ideally you get rid of all C/C++, but that may not be feasible. Combining Rust with some C/C++ still adds the benefit of Rust safety to the new code you write. The contained C/C++ is like the unsafe section of Rust code, a place where you have to be more vigilant, but you're slowly constraining the space where these issues can arise. And you can iteratively only replace those parts that cause a lot of issues.