Scala was absolutely killing the "we need JVM because all our Hadoop era tech uses it but we're a new generation of JVM data tooling and so we need a language in which the functional programming based abstractions we're using for our data processing are first class language features" niche for a while in the late 2010s.
Was a really big part of Kafka and Spark ecosystems until they supported Python well enough that a lot of people just stuck with that instead of teaching their devs to write Scala.