NFC reading is one. That's why lots of Governments publish apps - it's a reliable way to check your passport if you need a visa etc.

It might be coming to the web - https://developer.mozilla.org/en-US/docs/Web/API/Web_NFC_API

Realtime stuff. Audio, video etc, games. Apps with a large user library (like the Photos app) that should work offline.

A ton of features work only or better on app:

  - anything privacy sensitive
  - anything processing intense (using optimized binaries)
  - widgets
  - camera and audio based features *can* work, but are more finicky (or outright broken on ios)
  - local storage (exists in web app, short lifetimes on web site)
  - performance/latency sensitive work
  - (I'm less familiar, but probably local sensors, like gps and acceleration)

It’s also about friction.

No one wants to troubleshoot a card decline by logging into their mobile browser bank account in checkout at the grocery store.