The concept of a rigid “plate frame” style ballistic suspension system was pioneered by S&S Precision almost a decade ago. Benefits of a rigid plate frame are easy to put into a few sentences. The frame system itself absorbs no water. You can save weight using a skeletonized construction, without suffering from the sagging pouches normally associated with this approach.
Those attributes did certainly catch the attention of many amphibious and maritime units, which often have to carry relatively heavy loads on a small platform, which should be completely hydrophobic.