This whole subhread and this Elm mention are really interesting, thanks. Elm is a frontend language where I really understand the benefits of static more, because you're in a fairly controlled environment and your program isn't talking to a christmas tree of type system defying external services.

But for backend, the benefits of static sound attractive to me only on a program/product that is dominated by its internal business logic and has less interfaces to the unpredictable and constantly changing outside world. I think Darklang may be like this, from looking at the medium.com link?