When you get into a store to buy the essentials you need in order to be loaded for at least a week at home, having in-demand items at the front of the store is useful.
To begin with , placing in-demand items just in front of the location is useful for you as a customer because you do not need to waste time looking for the things all around the premises, specially if the place is big.
Second,it is useful for the store owners as they situate the things where they are best spotted and that guarantees the seller the purchase of the goods.
All in all, the position of the in- demand items at the front serves the purpose of the customer, who immediately sees what to buy and that of the retailer who wants their products paid for.