It is for printing labels for certain sets - like the mirrors aisle - that use small labels. We tie the label pog to the aisle, using a different section as the physical location - like (2) if the actual pog starts in (1). Not sure if this is always necessary, but you usually can only force an untied pog to print standard, not reverse.
We usually also print the whole regular pog so we can install the small labels in the holders on the front of the looped peg, and stick the full size labels onto the flat plate with the four pegboard prongs. Makes life easier for instocks because the small labels are hard to scan and also tend to fall out and disappear.
Because sometimes the label pogs won't worry like in the picture aisle. There is no adhesive on the labels.to stick it to the back and the label is too big for the small holders but you might need the shelf labels for 2-3 shelves in the aisle.