...groovy is still stuck with the "mistakes" of java as well which is what Scala attempts to fix with the rewrite. Kotlin is also a rewrite but does a great job of "fixing" java without causing the compatibility issues that Scala creates.
Kotlin is a nice language as is Groovy; they both provide similar functionality in different ways and compatibility with Java. Scala does NOT provide compatibility with Java. One advantage is that Groovy is much further along and much more widely adopted; it is part of the Android Development toolkit after all.
Logic doesn't apply to the real world. -- Marvin Minsky