It’s to certify that the image on the ID document is a true likeness of the person presenting it. The lack of face to face interaction makes the risk of money laundering a lot higher. The reason for asking now is probably because they have risk assessed you now you have gone over some threshold of deposits or withdrawals that they now need to complete more enhanced checks. Or they have just brought this initiative in to be more compliant with the regulations. There are big fines being handed out at the moment and a lot of companies are being caught with their pants down for not doing enough compliance checks.