I'm with you on this point. I generally won't find a team already using Scala. They are out there, but very rare. In most cases, you would be in a JVM shop, and have to convince your team mates that Scala is a good fit for such and such reasons.
Well, language features like implicit casting and variables make it a very hard sell, to say the code that we are producing is maintainable. Because it surprises Java programmers see things suddenly works because you have imported a package.