Over-engineering of course is bad by definition, but my point is that is not the correct characterization. Scala is both safe AND expressive which is good for b

Over-engineering of course is bad by definition, but my point is that is not the correct characterization. Scala is both safe AND expressive which is good for both productivity and reliability. If, of course, you take the time to learn and understand the core abstractions. To your point, yes that does take time and there is generally not a ready pool of talent you can hire with that knowledge already. So I wouldn't decide to write something in Scala if the team doesn't have any knowledge already and you're on a deadline, but you could say that about any language really. Any given team is going to deliver the fastest with the highest quality using the language and tooling they already are experienced with. But as an individual engineer I would say that it is worth learning. Even if you don't use Scala for any major projects due to various organizational reasons, it is a great, principled introduction to a lot of the patterns that are becoming ubiquitous is most modern programming languages. One of the small pleasure in life for the moment for me is when the NodeJS devs I know who always told me static typing is unnecessary and Scala was too "academic" are suddenly gaga over Typescipt and functional programming.