Google Flutter - What could be their reason for choosing Dart (over Kotlin)

Just a small side note:

It’s a big plus for Flutter that it has a platform-independent UI framework, and I don’t care whether components are rendered natively or not as far as users are okay with it.

However, there is also a considerable minus for Flutter. Generated binaries are huge comparing them to Kotlin/Swift counterparts.

I’m already receiving a lot of feedback to decrease the size of my app (~30MB). It comes with a lot of features and the size is one of the costs. I would never use Flutter for it because it would piss even more users.