Even for the most safety-critical software Zig might be easier to get it done. Or maybe not -- nobody knows. As someone who once worked on safety-critical software, the system could kill people if a computation took too long or gave a wrong answer exactly as much as due to undefined behaviour. Is it better to eliminate undefined behaviour at the cost of making other kinds of testing more difficult? Hard to say.

Rust's approach is based on one guess re correctness, Zig's on another. My personal guess is that Zig's approach is ultimately more effective at reaching correctness, but I could be wrong. There's no way to know which is better by thinking about it -- correctness is just too complex a subject.