The iPhone doesn't actually use NFC's peer-to-peer/"active" mode (since contactless payments aren't an NFC application; see my other comments on that), but it does specifically include an NFC "field amplifier" IC (shown in some iFixit teardowns), which most other smartphones and of course all physical cards/tags lack.
This does mean that iPhones can't do cool tricks like booting up the secure element purely from the field with a completely dead battery though that some earlier Android and Windows Phones could do (or at least Apple has intentionally deactivated that capability for a more consistent/secure experience) :)
This does mean that iPhones can't do cool tricks like booting up the secure element purely from the field with a completely dead battery though that some earlier Android and Windows Phones could do (or at least Apple has intentionally deactivated that capability for a more consistent/secure experience) :)