It's really silly – but Apple keep the NFC functionality exclusively for use by Apple Pay. Whilst it is NFC, Apple have never marketed it as such. Presumably they want people to think that it's just Apple Pay 'magic'.
Not just Apple Pay anymore, they also use it for certain transit cards and student ID cards. New phones can read tags and launch the appropriate app (via notification like Camera gives you for QR code reading): https://www.macrumors.com/2018/09/12/2018-iphones-background...
