Because it’s so difficult to get a towel from a manual dispenser…
From the site:
This is the paper towel holder that dispenses a sheet with a wave of your hand, preventing cross contamination and conserving paper. When the dispenser’s infrared sensor is activated, it advances the roll until its optical scanner recognizes the sheet’s perforations. It then holds down the paper towel for you to tear off with one hand, preventing germs from being transferred to the unused sheets and keeping the roll from unraveling.
Get One Here: Hammacher Schlemmer