No, rewriting in any language is bad by itself. What Fil-C gives you is that you don’t need to rewrite old programs. You spend zero effort, and immediately your battle-tested program is memory safe and free of any potential future vulnerabilities. With Rust you spend man-years on a rewrite, and as a result you have a new untested program full of subtle bugs, which you need to spend another 10 years of real-world use to uncover.