I had a small server written in Haskell but since the other contributor familiar with Java/C/C++ was not able to pick at it effectively, we switched to Rust and we all were happy, and transitioning was fine.

At work I deal with Java code, but we have a framework we wanted to use that's written in Scala, and since Scala can interop with Java, we were all productively able to transition over for the better.

For a hobby project we use Objective-C, but we are starting to write some bits in Swift. Apple is especially effective at trying to convince the developers to change over to this shiny language.

I think "advanced" languages can be used in real world applications, and the transition experience from other well known languages can certainly matter.