I'm a "pilot in command" kind of guy. I don't like handing off duties to software unless the software is bulletproof, and even then I'm still suspicious and watch it like a hawk. Because stuff happens and stuff really happens when complex systems interact.
The phone as key is not bulletproof. Far from it, though I hear you when you say your experience has been fine. Though I own one, I do not make a habit of carrying my iPhone. It sits charging most of the time, and days go by between picking it up.
So you see, having to carry the damned thing around would be a lot more onerous for me than slipping a small fob in my pocket when I need it and just going. Knowing the car will unlock, knowing the car will be ready to start, knowing the car is locked when I press the fob, is just a better deal than wondering....always...did it or didn't it? Will it or won't it?
And no deep dives into software workarounds required.
That's just me. If you're OK with the status quo, stick with it.
Robin