I had the same experience as you on the beginning. I started with a project in play framework, I was really excited about an improved java, etc. Then some FP hardcore developers came and started to influence younger developers that OOP was not cool anymore, all our system should be composed of Actions and monads of all kinds, and all business logic should be just a big composition of map and flatMaps.

After a while the project became just a dick measuring context of who could do the best trick shots. Declaring a lot of implicit parameters, implicit conversions automatically applied, crazy type inference that makes compiling 10x slower, you name it. Just to make the code unreadable enough that other developers need days to understand a three lines of code change.

And after all of that the more they do it, the more they are seen as the best Scala developers on the team.