Being written in rust is meaningless IMHO. There is absolutely zero inherent value to something being written in rust. Sometimes it's the right tool for the job, sometimes it isn't.
Please don't open a bridge to the Rust flamewar from the AI flamewar :-)
It means that it's not directly copying existing C compiler code which is overwhelmingly not written in Rust. Even if your argument is that it is plagiarizing C code and doing a direct translation to Rust, that's a pretty interesting capability for it to have.