Yeah, my father was mostly jesting, because it is undoubtedly a regular schedule or management's say-so when the store gets rearranged indeed, and not by the "polling at the register".
But in terms of the stores where we shop, the clerks at the register are empowered to help us look up an existing item, or to order an item that's not on the shelves, or even to place a new item on the wishlist. So it's more than small talk for them to ask that; it's an opening and an opportunity to find out what items are in-demand that they're not carrying, or may not be obvious to find if we're just wandering around the store.
Of late, I've found that clerks in stores such as Target and Wal-Mart are equipped with tools no better than the ones we have ourselves: that is, the mobile app or the website has exact information on store layout, item availability, and what aisle we can find this stuff in. Some Targets have spiffy kiosks which I can query without needing to call up stuff on my smartphone, but if I ask a clerk, their nose will immediately go into their own mobile device, just like I would've done.
On the other hand, smaller grocery stores that sell organics are likely to feature a cadre of very personable clerks who are intimately familiar with all stock and everything on the shelves, and they can immediately escort me over to where something is on a shelf, and make recommendations based on what they carry, and tell me how their logistics work. Without even glancing at a computer or screen!