Productivity is defined in subjective terms. I know several success stories of companies that use Scala as a better Java and find themselves more productive. That doesn't mean they don't do any functional programming -- it just means they don't need to use Scalaz/cats to be happy Scala developers. The OP is mostly concerned about Scala being a language that encourages the use of monad transformers and catamorphisms all over the place. What I'm trying to illustrate is that nothing could be farther from the truth.