Scenes are platform agnostic, and cannot (at least, should not) refer to Android's View classes directly. Instead, specialized Container interfaces form a boundary between the Navigational layer on the one side, and the Android View layer on the other side. This View layer needs to implement the Container, usually using View classes.
Often, it is not feasible or wanted to let the the root View of the layout implement this container directly, thus the need for an adapter-like class arises: The ViewController.

The ViewController acts as the bridge between the Scene and the View: it 'controls' the View if you like. It implements the commands the Scene executes on the Container, and redirects them to the view:

 1 class MyScene<MyContainer> : Scene {
 2 
 3     override fun attach(myContainer: MyContainer) {
 4         myContainer.text = "Hello, world!"
 5     }
 6 }
 7 
 8 interface MyContainer: Container {
 9     
10     var text: String
11 }
12 
13 class MyViewController(override val view: View) : ViewController, MyContainer {
14 
15     override var text: String = ""
16         set(value) {
17             view.findViewById<TextView>(R.id.myTextView).text = value
18         }
19 }