Everyone who thinks there is something underhanded about this is missing the mark, I think. The main reason is already listed - having pricing flexibility when wanting to go lower than the manufacturer’s MAP pricing requirements.
I have also found that another retailer strategy is to list an item as used (and e.g., as a 9 out of 10) to be able to sell it for lower than MAP/MSRP, but when you receive the item you realize it’s a brand new unit.

