You're conflating recoverable errors (Result in Rust, status codes or std::expected in C++) with the non-recoverable errors (panic in Rust, exceptions in C++).

If we were to compare Rust panics vs C++ exceptions, then handling of Rust panics is much less flexible. From what I understand, it's essentially a std::abort and it can be hardly used otherwise, which is only a subset of how C++ exceptions can be commonly used too.

If we were to compare Rust Result vs C++ std::expected, they boil down to pretty much the same with the difference of Rust requiring the call-site to unconditionally check for the return value. That may or may not be preferable in every situation.

> they don't need to pay the runtime cost of not-thrown exceptions that C++ users have to pay

Had this been true, which in 99% of cases it isn't unless you can support your claim, do you mind sharing how Rust implemented their zero-cost panics?