The idea
banks will flag up and block a debit/ credit card if it sees an "unusual transaction. such as mr ???? buying a duvet cover. mrs ????? renting a car. unusual so stop the transaction. this leaves the card user in a very difficult position. for example. forget the purchase? or hopefully have enough cash? or hopefully have another card. this has happened to me and my husband with monotonous regularity and its a major hassle.
Why is it important?
it drives us all mad