in the UK, they price items at £ ??.99 for when people traditionally used cash. this sytem at the checkout ensures that the staff member opens the till and gives a penny change. staff are not allowed to carry cash on the shop floor and all cash must be in the till and none on the top.
it stops customers from pocketing the cash, not ringing the item through the till.
it seems a bit crazy with this item. somehow i don't see someone walking into a store and pulling this item off the shelves, walking to the checkout and producing cash for it
(i'm just trying to find obtuse reasons for not going "I WANT ONE!!!!")