It's not actually glass, instead the apple engineers and designers are basically simulating effect of surface tension of drops of liquid. Unfortunately the refraction at the edges of a droplet is not informative about whether the droplet is inward or outward facing (i.e. if it it toggled on or off). Hence why they use additional highlights and shadow to indicate the 3D structure. The liquid effect is a total gimmick . And they added insult to injury by adding color-changes and movement which is totally distracting when you re scrolling that diffucult paper.
I know most people couldn’t care less about this, but those gimmicky animations probably consume more computing power than the entire Apollo project, which strikes me as unnecessary and wasteful. Given the choice, I’d much rather have a clean, efficient interface.
I tend to like Material Design in comparison. It’s clean, efficient, and usable. I just hope Google won’t try to "improve" it with annoying gimmicks and end up making things worse, like Apple did here.
"Flat" design is equally offensive by not demarcating controls as controls, or their state in an intuitive way.
Just as we were finally seeing UI step away from that BS, Apple jumps all the way back into much-scorned, cheesily-excessive skeuomorphism... adding a raft of failed ideas from 20 years ago.
Since this is in contrast to "wildly not flat and full of visual gimmicks": the modern "flat" style has severe (and very stupid) issues, yea. But "flat" has been around for a very long time in touch UI with clear control boundaries - just draw a box around it, maybe give it a background color.
That's better than plain text that just happens to be a hidden control, but text with a background color might just be... text with a background color, for emphasis. Or it's text with a background color, to distinguish it from editable text. A background color does not tell the user that it's a control.
A box around it? Slightly better, but still doesn't convey state. Sure, you can fill it in when it's "on," but that's still guesswork on the part of the user if he arrives to find it filled in already.
