The arguments I've heard supporting this are usually weaker than their proponents think because they simply don't understand the alternative. Even if this is true though, "banking" is much too broad a category to make such general statements. Consider:

> Here are some specifics – our new code is going to be an order of magnitude less in volume than the old and this is being conservative.

Java's static typing would help catch mistakes but it's not magic. And by moving this piece of their system to Clojure, they've managed to simplify it so much that there's much less room for mistakes to hide.