im not sure, but I think it might have something to do with the bank processing requirements. Some banks/CC's like VISA or whatever, any transactions require Full Name, DOB, etc.
Its not all cards, i know AMEX is like, slack, but i know here in Australia, that VISA/Mastercard/amex do have different... errr... 'requirements' for purchasing.
which is why some online places don't take Amex. OR Diners etc.
anyways i dont know the full details, but there could be a legitmate reason in some countries why BB requires this info.