Scala is not replacement for Java. It runs on JVM and can invoke java code, but has completely different approach than Java. Use Kotlin if you want Java replacement.
Also I would argue that Scala is much better suited for writing compilers than Haskel.
The problem with this approach is that 90% of Scala libraries are built by people that live in higher-kinded land, and believe that since they have reached that level of expertise, so should everyone else, the second they start learning the language. For instance, look at SummingBird: The hello world example includes F bounded polymorphism, and path dependent types! Anyone new to the language would run away screaming, and I'd not blame them.
Any examples of how it can help out?
Compiler today must interact with tools such as IDE. If you keep some basic rules, it is reasonably simple to write compiler which can interact with Intellij Idea and provide incremental compilation, live edit hints, error messages.
In Haskel you dont have any of that.