I think the tool can be of some help, when you set a specific individual and limit the ancestors and descendents, but yes, I agree, I don’t think it will be useful for much other scenarios other than if you have found some individuals with a lot of sources on FS.
Another thing is that when you use a tool like this, you need to accept the format given by the tool, for names on people, places and sources that is set at FS, and I know that a lot of both names on both individuals and places there has been transcoded and translated totally wrong. so as you say, the cleanup of the data can be a larger job than writing it manually of you try to batch import a lot of people…