There are some pains associated with Scala, though. Sometimes self-inflicted by people who want it to be like Java: for example, most ORMs for Scala suck. A team at my office tried to use Hibernate to disastrous effects (Scala and Hibernate's hostile takeover of collections don't play well). Even some DSLs like Scalike tend to also be painful and unwieldy. I also dislike Play and its multitude of quirks and incompatible versions.
It used to also be the case that both Eclipse (ScalaIDE) and IntelliJ IDEA were almost unusable with Scala, in particular constantly resulting in spurious compilation errors. I've no idea if Eclipse got better -- completely got rid of it after decades of using it with Java -- but IntelliJ did get better and mostly works (though it still cannot always compile Scalike DSLs).
But even with all of the above, when I have to work with Java code again I cringe. Even with all the pain, Scala is simply better to work with for new code.