I would assume this as well. But, I'm not sure how many people realize this, especially those who are accustomed to just using the MagicBands.I assume like other NFC taps you don't need to make contact with the reader for it to work.
Disney's web-site for it says the following:
Simply hold your iPhone, Apple Watch, or other smart device near an access point when entering the parks or using other available features, just like you do with a MagicBand. With Express Mode on iPhone and Apple Watch, guests do not even need to wake or unlock their Apple device, or open up the app, to use their Disney MagicMobile pass. As a reminder, valid park admission and a park reservation are required for park entry and must be linked to your account.