While you don't scan a barcode during online checkout like you would at a cash register, you will still use the number sequence under the barcode (also known as a GTIN) that uniquely identifies the product. The GTIN and barcode are still very important in fully digital store, like Amazon. The GTIN you provide to Amazon will go into their database. Amazon has committed to providing accurate data to their customers, who will look up GTINs to see who they belong to. So, it is even more important to have the correct, validated product identification in a digital world. You could lose out on sales and damage business relationships if you provide bad data.