+1 can you please backup your claim? Scala does not need to be Java popular to be usable (probably no alternative JVM lang will ever be as popular as Java - especially now that Java is evolving).
also, play is not "betting" on scala. Just because it was implemented in scala and provides a scala API that does not mean you can not use the framework from Java (or Kotlin, or Jruby etc.). If you do not care about the scala API, that's fine, use the Java API instead.
Speaking from experience? The reason why I am asking is because the post states "the fearful perception doesn’t map to the realities of the language experienced after consistent usage"