Many ecommerce integrations require SKU or barcode number for product identification as product titles are likely change more often etc. Although product details are exposed, the actual SKU number and GTIN are not.
It seems that the documentation is slightly misleading as well as this, the Product feed integration for Google is getting a false SKU. Eg. I have inputted HAD-100 as my SKU and I'm getting back a long string from the api (ref ID - this should be the product SKU).