I see your point (biased, but I get it), IMHO you are missing one fundamental aspect here…
Matteo
2011

Hi Matteo, I agree that the removal of the home button means the removal of a physical affordance. However, this has to be qualified with the following points.

First, the physical affordance of the home button was replaced by a digital affordance in the form of the persistent indicator bar at the bottom of the screen.

Second, the new digital affordance might not be as obvious as the physical home button. This is partially because the digital indicator bar isn’t annotated – but then again it’ll make the screen rather cluttered if it were. To be fair, though, the indicator bar is annotated in the lock screen. In the same vein, Android’s bottom navigation icons (for back, home, and recent apps) are also inferior to actual physical buttons, especially since the icons are in the form of arbitrary shapes (triangle, circle, square).

Third, the physical home button is a great affordance for going back to the home screen – partly because it was taught as the button to go to home. The button’s squircle icon doesn’t say “home” at all (if they wanted it to clearly say home they’d use a house-shaped icon). But Apple repeatedly reminded people that clicking the button goes home, tech websites repeated that information, and after a few generations it couldn’t be clearer that the button lets you go to the home screen. So the home button affords being clicked, but it doesn’t afford being clicked to go home. The latter bit has to be learnt. And it certainly doesn’t afford being clicked twice to switch apps, or being held down to trigger Siri. What I’m saying is that you might think the physical home button is an obvious affordance for going home (or even doing app switching or triggering Siri), but that was actually an acquired knowledge.

Fourth, in a similar way, the bottom indicator bar will have to be learnt as an affordance for going back home. In fact, Apple has been trying to repeat itself (and teach people) that swiping up goes home, because it knew from experience that you need to teach people how to use a product if it has a radically different design.

I know that there’s always a debate going on about why we should even require people to “learn” how to use something – if it’s well designed, shouldn’t it be obvious how to use it? But the thing is, there are always competing goals: aesthetics, usability, screen size limitations, etc. At some point, designers have to decide on a compromise between the goals. And Apple had exceedingly preferred aesthetics over usability even from the first iPhone. The point is, we have always been learning how to use the new features of the iPhone (and/or Android smartphones) every year. There can be an argument made that this phenomenon is bad. But that’s not what the FastCo article was going for. And the X isn’t really indicative of a sudden massive jump in the things-we-need-to-learn-to-use-our-smartphone.

And lastly, I think it’s great that you disagree with my article. In fact, it gives me an opportunity to learn new things and consider new perspectives. However, the way you’ve done it “I see your point (biased, but I get it)” is downright condescending. I think it says more about you than it does the validity of the points I raised.