Old articles of "Why Scala" talked about how great lambdas are, pattern matching, lightweight classes without getters/setters. Now Java does those things the reason to use Scala are few.
That's because these concepts where new and difficult for many people at the time. Now that they already know them from other languages (which is great!) we can directly start with the next batch of helpful techniques in Scala.
Java is still light years behind in terms of productivity through language features. (however, therefore it has higher backwards compatibility, which also helps productivity)
