Racewalkers and other performance walkers have long realized that the biomechanical designs of running shoes have performance advantages over walking designs. Many walking designs are made with fashion as their first priority. A lot of attention has been focused on cushioning in shoes as people are told horror stories about the effects of impact. Walking does not generate as much impact as running but requires more stability in footwear. A highly cushioned shoe tends to be less stable than a firmer one.
Softer shoes tend to be thicker and less flexible as well.
So for walkers, a firm, low profile shoe is preferable to a soft, thick one. Unless you have the time and resources to research and test all the new designs, a walking shoe expert can save you time, money, and a whole lot of trouble. Finding the right shoe takes a familiarity with the product that most people haven't acquired. An expert can analyze your walking style, your shoes, and your needs to match you with exactly the right shoe. They can also insure that you have achieved the fit necessary for proper functional performance of your footwear.