I think "strictly superior" makes sense in the way that Scala was never designed or intended to be a worse-is-better language like Java and people were willing

I think "strictly superior" makes sense in the way that Scala was never designed or intended to be a worse-is-better language like Java and people were willing to make that happen by evolving the language. It was never intended to be a Java-with-more-concise-syntax unlike some other newer languages. If something was clearly worse, it would have been changed years ago already. That some design is still there might suggest that some people just have a different minority opinion on some aspects. (Assuming that "strictly superior" does not mean "100% of devs agree 100% that this is 100% better than Java".)