I don't understand the question. We are talking about the way it in fact works. I'm guessing that nobody at the FAA or FCC has any misunderstanding regarding this fact.

Also phones don't meaningfully actually interfere with modern avionics. If your safety on the flight actually depended on hundreds of people clicking a button consistently every time the majority of planes wouldn't make it.

Mapping, navigation, listening to music, playing videogames, music instrument tuner. There are plenty of usages which don't require Internet/Cellular.

I often walk out of home with an old iPhone which doesn't have a SIM card and it does everything that I need it to.

The only thing that doesn't work is browsing the Internet or Messaging.