It may be superior if there's ongoing maintenance and improvements on the original code.
RiiR certainly has it's place though. Ripgrep for me as a user is vastly superior to grep and a large reason for that I see is in the safe optimizations allowed by the borrow checker. They're certainly possible in C, but it wouldn't be maintainable.
Also I'd look at how stable the library is you're wrapping and the size of the code base. It may be lower effort to rewrite than to wrap.
A good reason is that your fork is superior _and_ you have exhausted reasonable efforts at sharing the improvements with upstream. There's some threshold of how superior but it's subjective.
I think the author's point is not that you can't RiiR, it is that one should think twice if the resultant code is not supported. If there is a Rust community around it, great! But if it is just doing it just to RiiR, then (C) holds.
And what constitutes a good reason?
The epitome of open source is that you don't need to explain of your fork is really superior, the users will come.