As the thread title mentions, this is not only a credit on the Gold Card but also on some Delta cards.

So it depends if you only have the Gold card. Cancelling a card which has a benefit cancels that benefit.

If you also have one of the Delta cards with the benefit, and use that to buy gift card online, then of course it won't matter if you cancel the Gold Card, because in that case it was not the one that gave the benefit.

But, anyway, what's the point of cancelling the card if your next annual fee isn't due? And even then you have many weeks to play with.