Wow that was easy once it was explained... Thank you internet stranger. I can now operate the device I carry on my person all the time with a little more grace.
I may be the only person who has never taken the time to figure out how to intentionally call the reachability feature. I just know that sometimes everything shifts down on the screen and it has never been on purpose, and then I have to figure out how to undo it - usually by turning the screen off and back on.
I am on the 11 (I think? I've lost track, but its the one with three cameras), and the screen is slightly too large for easy one-handed use, at least in my case. I might opt for the mini if/when I decided to get a new phone, but throwing $1000 at a new toy just because it's slightly more comfortable in my hand feels like a very "first-world" solution to a not-really-problem. None of the other features this phone comes with feel like they bring any extra value to my life or warrant an upgrade.
But hey, newer, faster chips mean it can probably run Doom now, right?
There's also potential for asteroid mining, building space/lunar colonies. Not to mention Musk's dream to build a Mars colony. Plenty of "wow" factor for space exploration, imo.