Originally Posted by
freezingflyboy
I've never used (or know what) a Z31 is. I usually just book through the app. The rates are usually as good or better than anything else you're going to find online and often there are special deals. For example, I just booked a Bonvoy property in downtown Atlanta for a family function and for a few bucks more it included tickets to the Georgia Aquarium.
I've routinely gotten a pretty hefty discount using any of the 3 ATL Marriott codes over booking just on the app. I got stays and points as well.