Are phone photos enough for food product photography, or does the difference show?

No, when the label and the batch code have to be readable on the shop listing. A phone can flag a shelf, and it stops working if that picture is the pack a wholesaler buys from. Put the pack next to the phone photo and see whether the label text reads in full. In sierra shops the shine on the plastic hides the batch, and the order arrives as another reference. You get the file of the pack, label readable, for the listing and for the wholesaler.