'Tis true that the backs have never been withdrawn from sale but try to load film into an H3 or H4 and perhaps it might become understandable why the H4x may be important for those using the H system for primarily film usage. Whatever ones opinion of a "rebadged Fuji camera" I found it rather positive that a manufacturer feels it worthwhile to spend on developing the upgrade, investing in the process of enabling this and be presumably willing to support through sales/service the product into the future.
Sure, it it most likely to be a professional use camera but perhaps it is indicative of a professional level demand for up-to-date film usage cameras. As a committed analogue user (whatever I personally feel about the H series) I found the subtext of the announcement to be more uplifting than reading about another film/paper not being available.
Well, Fuji does manufacture film. It makes sense to me.