You are correct, you can do that. However, as pointed out several times, if you use the CustomUI editor to edit the UI, you're typing the xml manually and thus cannot use the applications ribbon management tools. Two very different solutions for customizing the ribbon. Let me see if I can explain a little more succinctly.
Customize the ribbon via the application management tools
- You can access this via File > Options > Customize Ribbon/Quick Access Toolbar
- You can only choose from a set of built-in icons
- You can add a custom ribbon tab
- You can add a custom group to any ribbon, custom or built-in
- You can only add button type controls
- You cannot edit the backstage view
- You can choose from an available macro in the workbook or [public] in Personal.xlsb
- You cannot use dynamic callbacks
Customize the ribbon via CustomUI Editor
- You must write your own xml
- You can use any built-in imageMso or import a custom image
- You can add a custom ribbon tab
- You can add a custom group to any ribbon, custom or built-in
- You can add almost any type of control (i.e. button, menu, splitMenu, etc.)
- You can add UI elements to the backstage view
- You can assign any [public] macro in the containing workbook (not recommended to link to Personal.xlsb or other files)
- You can use dynamic callbacks