Maybe not to the customer, but it matters in general because Bitpay and others are pushing Bitcoin Cash as a solution to this on the basis that it has lower fee

Maybe not to the customer, but it matters in general because Bitpay and others are pushing Bitcoin Cash as a solution to this on the basis that it has lower fees because of its bigger block size (also because no-one is using it, so the blocks are almost always far below the Bitcoin block size). They likely stiffed him on the transaction fees for the return transaction too; the Bitcoin client's recommended fees are already on the conservative side, and they charged more.