Somebody linked a comment from an Ubuntu maintainer where they said they want more resilient tools.

If license was the only concern then I'd think that they wouldn't switch the programming language?

And yeah, obviously using Rust will not eliminate all CVEs. It does eliminate buffer overflows and underflows though. Not a small thing.

Also I would not uncritically accept the code of the previous coreutils as good. It got the job done (and has memory safety problems here and there). But is it really good? We can't know for sure.