Originally Posted by
disneyfriend0530
they are not useable for "non-refundable/early web special rates" since these are discounted rates already
They gave you the right answer but the wrong reason. The reason you can't use travel cards with those rates is because they're non-refundable, and thus prepaid. It has nothing to do with the discount.
Any rate that's prepaid, there's nothing more to pay at check-in, which is why you can't use a travel card toward that stay.
A travel card can only be applied at check-in for charges not yet billed at check-in time.
So it all has to do with billing, and not with discounts.