I don't think this is true of every financial institution. Nubank runs almost entirely on Clojure except for some of its Data Science tooling which is in Scala. Sure it's JVM, but it doesn't exactly scream risk-averse to me.
Is there only one possible solution for each board? Today I felt like deriving contradictions was a lot harder today than usual, but I still ended up with the correct answers.
I think there should be a way to mark dominos as "confirmed" vs "guesses", because not everyone is going to have working memory to remember which tiles laid down are "guesses" for deriving contradictions.