I'm not worried about learning Dart. I'm worried about adding yet another tooling and OSS ecosystem to my collection, that's where the real cognitive burden is.

I'm not worried about learning Dart. I'm worried about adding yet another tooling and OSS ecosystem to my collection, that's where the real cognitive burden is. I'll do it if I have to, but in mobile you really don't have to. You can choose from Java/Kotlin, Swift, .NET, and HTML+(Java/Type)Script - chances are you're already in one of these worlds, and if you're not then entering any one of them will pay much bigger dividends than Dart.