Of course the editor is intended to do things manually. I never negate that and I fully appreciate powerful tools it brings. But all I know about computers is that, they are the best at doing repetitive things and i love to exploit that.
Imagine situation like this. You have car store. Every panel in Your store is composition of nodes (Panels, Sprites, Labels, etc. and the like). Suppose You have to add new car to the game. You must remember to add new panel to the store and adjust all its nessesery data. Of course You can do it manually simple by Ctrl+D and clicking and typing to change information on panels. Every time You want to change something in the store, You have to find it in the nodes structure, then click and type. And beacuse there is a lot of steps to do, it's time consuming and there is always a chance You'll make the mistake.
But if You have tool script which is feed by nessesery data, You can use it to update the store for You, whenever You add new car to the game or change something in car data. If You have such mechanism all You care is to update your base data file.
And this is the Idea I have used in my game for creating repetitive nodes in the editor.
When I made that mechanism I realised I could automate process for creating nessesery resources, e.g. SpritesFrames which I have a lot in my game. I made working editor plugin which makes nessesery resources based assets stored in the project, add attaches them to corresponding scenes and saves them to the disk.
But I dreamed about situation in which only thing I must do is to put the name to plugin and decide where to write it. Not only for resources ( which works) but for creating inherited scenes (which is currently impossible).
And thats it.