"Magic" syncing, spatial audio, and transparency mode are likely top three.
Many people didn't see how iPhone was better than its competitors at first either, mostly because they were focused on the things the competitors emphasized and dismissive about what Apple brought to the table. Until, of course, those things because all any company was trying to deliver.
Computational audio is another, it has the H1 chip, its gonna be Apple exclusive algorithms that make soundscape absolutely bonkers. Sort of like Dolby proprietary stuff.
Many people didn't see how iPhone was better than its competitors at first either, mostly because they were focused on the things the competitors emphasized and dismissive about what Apple brought to the table. Until, of course, those things because all any company was trying to deliver.