Tbh I suspect part of the value is that it limits the amount of absolute junk filling the store. Requiring a unique ID for every product that costs some money is a very low bar for real products, but a high bar for AI generated slop tshirts that might not sell a single unit.
Interestingly, it doesn’t look like IKEA uses UPC barcodes at all and just has their own format and numbers. I guess since they only sell their products in their own stores, there is no need for it to be globally unique.
I've never seen actual junk that doesnt work from a fake brand with a legit UPC barcode, which seems to indicate it's an effective gate keeper, if people cared to look at it.
Interestingly, it doesn’t look like IKEA uses UPC barcodes at all and just has their own format and numbers. I guess since they only sell their products in their own stores, there is no need for it to be globally unique.