Eliminating some obscure bugs from C code is not worth intruducing a lot of new bugs. GNU coreutils have been used and polished for so long, that it would be far more effective just to fix the issues as they reveal right in the original code. If rewriting removes one kind of bugs while introducing another - then what’s the whole point?

I cannot imagine obviously buggy code from 2020s being more secure than code that has been around since previous century. Again, even if Rust for real is a better solution for security reasons, the way it is being developed and shipped is not how one makes software more secure. Disregarding the license, uutils look like something pursuing hype, not strategical benefits.