Recently a news story appeared about the globe used in the recent film, Valkyrie, starring Tom Cruise. See here http://www.huffingtonpost.com/2009/01/02/tom-cruise-may-face-legal_n_154748.html
The globe, taken from Hitler's Berghof, near Bertchesgaden, in the Bavarian Alps, after the end of the war, appears quite an ordinary one, probably produced in the thousands. It would afford little detail for "planning" anything. But, then, Hitler was not much of a detail person, as he "set" overall policy, usually as a result of his lieutenants asking him questions to obtain a sense of his thinking. His interest was more in architectural plans for Berlin after the war (a new imperial Rome on the scale of his meglalomania), which suited his artistic side. Now, that would be a set of interesting documents!
Globes and maps, of course, can be used for their symbolic value. Re this, a more interesting article about some Nazi globes is here http://www.nytimes.com/2007/09/18/arts/design/18globe.html
Also, Mark Monmonier writes about Nazi cartopropaganda in his How to Lie with Maps (chapter 7).
The Hitler globe appears quite ordinary, as I said, with probably hundreds of copies extant. Second, to say the Valkyrie props department made a "replica" probably greatly stretches the facts. The movie set artists would have no reason to place literally thousands of minute pieces of geographic detail--toponyms, etc.--on the movie-version globe. The globe used in the film, then, was a facsimile used for its overall, authentic, period appearance.
Then why would the present globe owner make such noise and threaten lawsuit? Publicity for the globe and for the owner--self-aggrandizement--is most likely. It makes for a good, and easy, story and adds monetary value to the globe itself (think resale value).