My alma mater recently switched to Scala for its intro courses, my undergrad thesis mentor really pushed for it and has written an intro textbook using Scala.

My alma mater recently switched to Scala for its intro courses, my undergrad thesis mentor really pushed for it and has written an intro textbook using Scala. He's also the reason I used Scala for my senior thesis, which led to me suggesting it at the startup I work for (first hire) and Scala becoming the basis of our backend. I think the OP really nails the reasons Scala makes sense as an intro language. Students can start with simple concepts and gradually see how these lead to the complicated stuff.