They are toning shoes with a gentle but definite "rocker" profile. They are supposed to help you firm up more muscles (or perhaps different muscles) by making you work more as you walk.
My wife reports that walking on concrete is easier on her feet with these than with traditional flat-soled walking shoes. Also, she was trained as a stitcher many years ago and when the stitching department in her production line gets behind, she goes down the line to help them get caught up. If you have ever seen an industrial sewing machine used in shoe-making, you'd notice that the basic functions of the machine are controlled with foot pedals. Those women have to stand in one place all day, and many have moved to the toning shoes because the rocker in the soles helps take a bit of stress off what is essentially a highly repetitive sequence of moves with their feet.
If NB ever produces them in widths that can fit my "paws", I want a pair for walking. I am a heel-strike strider and that is exacerbated when my dog decides to stop heeling and get ahead of me.