Command Bars allows you to easily save and load your Command Bar layout to and from a String. You have more control over what Command Bar customizations are saved/ loaded when saving/loading the layout to/from a string. When saving to a string you have the option of saving the customization settings from the Keyboard and Options pages of the Customize dialog, you can save only the layout of the Command Bar that have changed, and you can chose not to save the Command Bar layout. When loading the Command Bar layout from a string you have the option to restore the controls layout, options layout (Keyboard and Options pages of the Customize dialog), and whether to prompt the user before restoring the layout.
Some applications have multi user access. It can be useful to store a layout for each user in a personal file instead of the registry.