I'd agree with this. I think it's because if you're writing a web server then you're probably settled on one way you're going to deal with say asynchrony - plai

I'd agree with this. I think it's because if you're writing a web server then you're probably settled on one way you're going to deal with say asynchrony - plain futures or cats or whatever. But Scala has this level of abstraction above that where you can write a library that doesn't care which of those you're using and just slot in around your choice. What it can't avoid is that as soon as you jump into the source code of that library you see all these type classes everywhere and have to mentally fit your concrete use case into those complex looking function signatures that probably use concepts you're not using much in your actual application code. For better or worse it's super easy to write application code in Scala without going to a very abstract level, particularly in an ecosystem like Play. And that does make library code feel less familiar because it's using features that you just don't necessarily use very much in your application code.