I will [subjectively] confirm it. I've rebuilt two startups from Scala / Python messes with Haskell. Turn around time was counted in weeks (original build time

I will [subjectively] confirm it. I've rebuilt two startups from Scala / Python messes with Haskell. Turn around time was counted in weeks (original build time was > 6 months), code is clearer, many unhandled edge cases were illuminated by the type system (some simply due to the rewrite), bringing in another Haskell programmer was painless and he was able to safely refactor the entire code base to make it even cleaner and robust while operating in production with zero regressions and no unit tests. We can iterate faster, the type system prevents us from doing dumb, fallible human things, it makes it easier for other programmers to get up to speed, it is fast, the community is brilliant, and because of its static guarantees open source tooling (even if abandoned) is possible to use because of the aforementioned ease of coming up to speed, the type system is a stringent form of documentation, and you can tweak without fear of introducing regressions (mostly, I can't say all but definitely most).