The entire reason I purchased a gift certificate was to avoid entering CC details whenever possible.

Why cant I purchase Items with just my accounts existing credit without a CC?

The gift certificate system has to track the amount/portion that has been used and what is still available. We do not have another way to track that currently.

Sigh, the store has as expected has ignored my gift certificate code and used my CC instead.

Please be sure to click the blue + sign to the right of the code once selected to apply it to your order. You should see the amount applied reflected in the total to be paid before placing your order.

I did click it.

You need to make sure that the order summary on the right is correctly updated after applying your coupon and/or your gift certificate.

If the Total remaining reduces to zero the Choose a payment method section on the left should change to indicate that no payment is necessary.

I just placed this order - didn't need credit card details, although it insisted on address details.