Regardless of Scala, it's an absolutely insane idea to develop your own language to write your apps. Either stick to the real Scala or switch to Java or Kotlin, but writing your own language is a failure waiting to happen. I give this project a few more months before it gets canceled.
Funny you should mention Kotlin, as it's the result of JetBrains doing just that: developing their own language to write their apps. Mozilla represents another successful example with Rust. I'm of the opinion that developing new, purpose-built languages (or extending existing ones) is a strategy that isn't given as much consideration as it should.
JetBrains is in the business of IDEs and similar programmer tools. Kotlin fits right in with the rest of their business.
Imagine if JetBrains produced a chatting program, because their engineers were not satisfied with the existing options.