No idea about the commercial prospects but if you haven't used any modern statically typed languages yet (Haskell, Rust, Scala, maybe ML/OCaML, or some of the more pointy headed ones like Coq) then I think getting some understanding of these is an important part of your tool set, even if you don't use it at work. They used to say the same thing about Lisp and it's still true.

I've spent a fair amount of time on Haskell and it's been worth it even though I haven't ever directly used it at work for anything significant. Rust at worst seems the same way.