While blowing, some of the fan’s energy is spent on increasing the pressure inside your dishwasher, which increases the density of the air the fan blades move through, increasing drag on the fan blades causing them to move slower and create less airflow.
While blowing, you’re also pushing moist air to the back of the dishwasher, and after that air reaches 100% relative humidity, it can’t hold any more water and will not help dry your plates. Some of it will eventually escape around the sides, but some of the airflow your fan creates just circulates humid air around the inside of the dishwasher.
Turning your fan around solved both problems. It increased the volume of air flow, and decreased the relative humidity of the air flow.
The capability itself is concerning. This bespoke cable might cost $200, but what would the unit cost be if a state decided to mass produce them?