Purely functional programming in Scala is currently hot, and there is a lot of interest for it. However, I still see lots of people wondering why they should use libraries like Cats in first place.
This is why I have created http://functorhub.com/ - an online course website dedicated to Advanced Scala only. So far it has only one course that will introduce you to Cats, but this will change over time!
If you are confused on why you should use Functional Programming, and what things like higher kinded types, type classes, Monads, Cats etc are all about - you're welcome to check it out!
Also, if you have anything to say, any feedback is very welcome!