I'm assuming that this works in your channel right now and you are asking about the future. SceneGraph is relatively new, so there's that, but Roku is pretty slow to remove things from the firmware. You're always at their mercy anyway, so if it was me I'd go with it and worry about it when it breaks. Who knows? There might be another solution when that day comes.
Albeit don't see it being necessary either - assuming you are using only one scene, you can always get that by calling m.top.getScene() from any thread (and in the main() thread can do that with screen.getScene())