I don't think I could disagree more with your number 4. Adding a boarding pass to Apple Wallet and having it update itself with gate changes, delays, etc, notifying you and even scribbling skeuomorphically what changed on the pass [0] has been one of the strongest delighters I've experienced in recent times.
Are you not also paying attention to the gate itself and to departure boards? Why do you need your phone to tell you what's posted on numerous displays that you walk past?
So you disregard what's in front of your face, in preference to your device.
Other folks here were talking about how their devices did not update in a timely fashion. They had to force refresh several times to get a response. Meanwhile the gate screens have a single job and update within seconds.
My apple wallet boarding passes never update on time. At LAX they sometimes put you as a placeholder at the international terminal for your gate on boarding pass. So then you show up, slog through the international terminal to this gate, and see that no you are actually in terminal 7. Enjoy the resulting 2.5 mile walk I hope you baked in extra time.
Now I don’t trust it. Googling the flight number brings in the updated gate. Not the apple wallet boarding pass though.
You can do that with a boarding pass downloaded from the airline website or emailed to you by the airline. But some airlines like to hide this option in order to force you to download their app.
Why would you need to do that? The boarding pass has a QR code on it; the QR code links to your ticket. If you need to change your booking, they can email you a new one.
And? These are available on google, on the airline's website, and on screens throughout the terminal. Many airlines will send them to you via SMS. There's no need to have a whole app just to check your gate assignment.
[0] https://i.imgur.com/OkthcOi.png