Why do I need this addon if I already have "Tree Style Tab" from the same developer?

The description for this addon lists the menu items that will be added, if used in conjunction with Tree Style Tab, but those menu items already exist in Tree Style Tab without this addon installed.

This is confusing.
Have the features from this addon been merged to the Tree Style Tab addon? Is this addon now abandoned?

This is a confusing mess for users to figure out.