To be clear about the chronology here, wycats made the decision to go with Rust, then did a lot of work in Rust, then became a core team member. He chose Rust because of his needs in Skylight, not because he was already invested in Rust.
https://blog.rust-lang.org/2014/12/12/Core-Team.html
> Yehuda Katz will be known to many in the Rust community for his work on the initial design and implementation of the Cargo project. He is also a co-founder of Tilde, which has been using Rust commercially in their Skylight product for quite some time