iOS18 Control Widget that opens parent app

I feel like this is probably really easy and hopefully I'm just doing something stupid, but I can't get a control to open the app it belongs to.

Taking the intent itself directly from the example code, and it does nothing when the button is pressed.

struct OpenAppWidget: ControlWidget {
    var body: some ControlWidgetConfiguration {
        StaticControlConfiguration(
            kind: "com.dfjkldfsfrw.ControlCenterWidgetDemo.OpenApp"
        ) {
            /// This one - based on the demo code - doesn't work on simulator or device
            ControlWidgetButton(action: LaunchAppIntent()) {
                Label("Launch App", systemImage: "arrow.up.right")
            }
        }
        .displayName("Launch App")
        .description("A an example control that launches the parent app.")
    }
}
 
struct LaunchAppIntent: OpenIntent {
    static var title: LocalizedStringResource = "Launch App"
    @Parameter(title: "Target")
    var target: LaunchAppEnum
}
 
 
enum LaunchAppEnum: String, AppEnum {
    case timer
    case history
 
 
    static var typeDisplayRepresentation = TypeDisplayRepresentation("Productivity Timer's app screens")
    static var caseDisplayRepresentations = [
        LaunchAppEnum.timer : DisplayRepresentation("Timer"),
        LaunchAppEnum.history : DisplayRepresentation("History")
    ]
}

I've tried adding a perform( function to the intent, and setting openAppWhenRun to true, but they don't seem to make a difference.

I've also tried using an OpenURLIntent in the result of the button's intent to open the app based on a custom url scheme, but whilst that seems to work in the simulator, it doesn't work on a real device.

What am I missing?