What are the benefits of buying books with a sticker over the original bar code? Are they cheaper than books without the sticker?

i think its only to resell books with their own barcode as if you sell with same barcode you cannot create your own listing so most of the book sellers buy their own barcodes so they can have their own identity over the publisher and whenever some one will search at website then customer can find their website easily for the same book to buy again or recommend someone to buy it easily. its a good trick to create your own brand and you can have cheap unique ISBN valid for ebay amazon and websites from