There have been some instances of this before; at least one game was implemented in Rust. But, given the length of the Warp waitlist, I'm pretty sure this is the most popular application so far. There could be things I don't know about though, at this point Rust is big enough that not everyone who uses it talks about it publicly.
I forget the status of that, you may be right! That'd be a large deploy too. The intention was to do that, for sure, I'm just not sure if it shipped or not.
