>>>I have no idea what Paypal is trying to achieve by passing on this fairly personal piece of data.
For years the Paypal API sucked, and even today their are many companies that do not have full integration with paypal, so this is a way to match payment records as for 99% of shoppers the email address for the order/account will match the paypal email address.
For years the Paypal API sucked, and even today their are many companies that do not have full integration with paypal, so this is a way to match payment records as for 99% of shoppers the email address for the order/account will match the paypal email address.