As a retailer you do not want customers coming in and only leaving with a few items, you want them to come in and fill a cart as full as they can get. To have them do this you have to make it easy for them to do it or they WILL NOT...
“the old 5 and 10 store philosophy was “if I could get a nickel from each customer” was the way to success.”
Moving as much product in volume as possible every 24 hours equates to lower cost prices from vendors and wholesale suppliers. This savings is your first profit margin before you ever even sell it to the customer. And cash flow is king, more volume per day lowers your overhead cost percentage per day.