Bigelow Aerospace develops expandable (inflatable/foldable) space stations. Their flagship is their cylindrical BA330 which has the dimensions 13.7 by 6.7 meter when expanded. Current ISS modules seem to have a diameter of less than 5 meter. But this is not far from the dimensions of fairings of Atlas V, Delta IV Heavy, Proton and Ariane 5. They have 5.0-5.4 meter fairing diameter. The mass of the BA330 (20-23 tons) is on the limit of what those rockets can launch to LEO. SLS might get fairings with up to 10 meter diameter.
So why go through the extra trouble of making their space station expandable? Is the extra 1.3-1.7 meter diameter so important? Wouldn't a static structure, maybe made by the same materials, be much simpler and cheaper to develop and manufacture, lighter and less risky to deploy in space?
If the BA330 is primarily a technology demonstration, what would be the use of space station modules which have larger diameter than the payload fairings of today's and near-future launchers?