Wow! Thanks Wolf for taking the time to provide the response! I can understand from the above a reason to use Control. My need was only for a parent container for the TitleValues. I wasn't looking to try to find the perfect answer :-). My concern is that worrying to such low detail is expending energy on something that makes no real impact on the final delivery. IF I worried about every little aspect like this, I'd never write code; I don't want to sound arrogant or flippant; what I'm trying to say is, YES, you are correct. If I were building a large GUI will buttons and controls, then using the Control as a parent would make more sense. However, it is just a simple container to hang the TitleValue's of. I'll happily change it to control now, going forward, but in the scheme of things, it isn't important.
In fact, I've just changed the node to Control; this then breaks the game.
Control doesn't have all the positioning on the screen, i.e. Z-Index. Therefore I now would have to create a Canvas too and then set priorites; but with that, I lose visibility!
RE: Tutorial (Godot Engine v3 - GDScript) - GUI for score & lives!