SwiftUI failure with @binding and @State

SwiftUIPlayground.swift

struct SwiftUIPlayground: View {
  @Binding var isOn: Bool

  var body: some View {
    Text("ON").scaleEffect(isOn ? 10 : 1)
  }
}

struct SwiftUIPlayground_Previews: PreviewProvider {
  @State static var isOn: Bool = false

  static var previews: some View {
    SwiftUIPlayground(isOn: $isOn)
  }
}