It's quicker to glance at icons and spot the app right away than not read each and every item in a list.
Going back to the original article, it doesn't really matter what the icon looks like, as long as it's unique. You're not looking at each icon and asking yourself "is this a camera?" to get to the Photos app. You know it's a circular array of colors, and your finger goes there.
Really? Because when I used an iPhone, I most definitely didn't know where most of my apps' icons were. I knew most of them on the first screen and the rest of the screens were a mix of random stuff.
Back in 'teh day' when my icons were all cutesy skeuomorphs, my computer came with maybe a dozen apps and most of them were on my desktop. Now, I have over a hundred sitting in my global Apps folder alone - never mind user Apps, sub folders, etc.
This gets compounded even more on phones - on my iPhone, I've accidentally placed 1Password next to the Settings app - both have a grey background with a circular center. Settings' center is grey gears, 1Passwords is a blue ring with a keyhole. On examination, they're not similar at all, but I can't even begin to tell you how many times I clicked on when, meaning to click the other - even _knowing_ the differences and kicking myself each time.
I think a lot of what the designers are trying to do is create an icon that stands out visually, and is easily found from amongst a large set of other icons, rather than trying to impress upon us what its functionality is from a metaphor.
I'm far faster at picking text labels from a list than picking the icons. I see the text label as an icon.
The text "icon" is simple and unchanging. I can pick it out much faster than funny pictograms that change with each OS version.
Tell that to my muscle memory that types ⌘A > iP for iPhoto and ⌘A > iCal for iCalendar.