This is the way it’s always been though. First it was Java, then Ruby, then Clojure, then Go, then Node, and now Rust. As languages get popular, multiple projects get rewritten in them. At first it’s a novelty, but it is often useful to see what the strengths and weaknesses are of a language to implement an existing project. Eventually, it becomes annoying to have “written in X” attached to articles and links, but soon, that will diminish.

The only time when I think it’s really appropriate for a mature language is when the language itself is a feature. But that is really rare for that to be the case.

Other languages (eg Python, Haskell and Erlang) are in the mix too, but more evenly distributed and less fad-ish.

This is just part of the hype cycle of languages. I’m not saying Rust is only a fad, but we are definitely in that part of the cycle for Rust.