It's not part of Javascript, so you'll always need Babel (or similar transpiler) as a dependency and some kind of build step.
It's additional complexity when you could have solved the same issue by using better design on the API level.
It's additional complexity when you could have solved the same issue by using better design on the API level.
I don't intend to ever write un-typed, naked javascript again if I don't have to.
Even scripting, ts-node is perfect for it.
And as far as complexity - I find typescript to be far better than webpack/babel in configuration and UX.