A word of warning (based on what happened to me just now and another time in the past). If you already have a reservation that you booked on-line - there is an option to "change reservation." This allows you to look for other discounts that may come available, change resorts, dates, room type, etc. IF you call and have them apply a promo, like the Visa promo, you will no long have that option of changing your reservation. The button to do it just goes away! From then on, you will have to call to make or even look for other resort options.
For me, to save $27.33 at POP with the Visa discount and no longer have control of the reservation, is not worth it. It took a long time on the phone to have them remove the Visa discount, once I looked at the on-line reservation and realized what happened to the ressie.
Now it is back to the way it was, at rack rate. But, at least now I can change resorts or dates if we decide to. And, I can even look for other "vacation offers" like when the AP discount or FL resident discount may become available. All this I can do myself on-line, without calling and going thru the whole phone thing and relying on a CM on the phone.
Only my experience. Just wanted to pass it along.