It’s probably just marketing, the super high stack is visible from far away and advertisers many available colors. If one catches your eye, you then have to walk through a bunch of other aisles to actually get to the towels. It’s like putting the milk at the back of the grocery store.

I could see this be a way to show how the towels look like when neatly stacked. And to show what belongs into that shelf if it were empty.