They suggest other products a customer might be interested in.
More and more data about each customer will be available.
It would have been much more convenient if the customer under the sheet had been Jeffrey Byrne.
He announced to Dean he had answered the door and a customer was waiting.
So that if, for example, a fishmonger uses such a machine to ascertain the weight of a piece of fish which he places in the goods - pan, and thereby depresses it down upon its stop, and then places weights in the weights-pan till the goods-pan rises, the customer is charged for more than the real weight of the fish.