I am not a Scala developer but I try to learn it. I think that the problem with Scala, as well as with C++, is: It has too much features.

I think it is better to learn several programming languages that one overloaded.

Whith an overloaded programming language you have: A very few programmers that understand the whole thing and others that understand only some parts.

Whith several simple programming languages you have: A very few programmers that understand all the languages well and others that only understand one but well.