Actually, the CM at the parking booth will have an handheld scanner that can determine if someone is eligible for free parking (resort guests/passholders). They may ask for a photo id or the name associated with the pass.For annual pass free parking at the parks you show the card at the booth.
We were told by a CM in one of the Poly gift shops that they could extend the merchandise discount if we showed in the app that we were DVC and/or had an AP.Over Spring Break all the did was look at the MB -- never bothered to scan it. For park discounts they said -- EVERY TIME -- "I need to see your AP card AND photo ID," so I'm not sure you could get away with the app. It's not really worth the hassle, just bring it.
Activated APs in December, only card we were given was the yellow discount card. Nothing else. They told us that the band was all we needed.
Seems like it depends where yo activated. We activated ours at MK since we were staying at the Polynesian. I remembered years ago when we had the old paper type AP cards and expected something. When I asked the girl at the desk said nope, just use your band.We activated our APs in March at Disney Springs & were given actual card APs, no discount cards. Ordered AP Magic bands when we got home. We are going back Monday - I always have my AP with me in case MB doesn't work & they need proof. We were told always to carry the APs.