Rust is a cult though. This will get upvotes that just "re-implementation of non-Emacs text editor" wouldn't.
The implementation of Xi, has some novel things that might interest Rust programmers, like a practical Rope implementation, which are quite rare in Rust and often abandoned.
I was interested in Rust before, but it now seems like Rust programmers are like vegans (I have to hear about it every 10 minutes.)
I'm not saying anything specifically about this case, because clearly the information here is very limited, but there is a case to be made for rewriting projects that work to increase maintainability in the future. Most newer languages do have an edge in this department, as they are more conscious of those issues.
There is sometimes the benefit of a rewrite regardless of language, as well; cleaning stuff up, organizing stuff better because you now know better, etc..