I beg to differ with the info about 4k being too small, especially for those of use using a lot of visual media. Obviously there are 4k 80" HDTVs, and 4k 15.4" laptops. And 4k tablets. And probably 4k 50' stadium displays. ALL display the same info, 3840x2160 pixels. So, if you say cropped your image to that pixel size, it would be exactly the same info on all of that screen real estate.
So is it too small? one could only determine that once one knew the viewing distance. Each of those example has very different PPIs; high pixel density for say a phone or tablet (264 PPI for a 9" iPad), a bit less dense for a laptop (say 226PPI for the new 16" MBP), a bit less dense for the 5k iMac (217). And note that because of the retina system most people don't have issues reading on Apple retina displays from iPhones to iMacs. So if that monitor is a few feet away, then yeah, having big pixels and such might work fine, even though it means sacrifice the amount of content you can see at once. But get close and yikes, screen door effect. Like why we had to sit across the room to watch standard def TV. But again, it's easier to enlarge an image on a hires screen and get good results than the other way around; you lose info trying to cram in more content on a low res monitor.
And the info in that article must be some PC stuff. MacOS uses hires graphics. In other words, in macOS retina aware applications like say Photoshop, Lightroom, and so on, the user elements are literally twice as large in each dimension on say a 4k or 5k display. Since they're using a 200x200 icon instead of a 100x100 icon. You can see the difference. For example, I ran a 2.5k 27" monitor (old iMac PPI) right next to a retina iMac. If you took out a ruler and measured the Safari icon it was exactly the same dimensions on both screens. But the icon on the iMac was far denser, with more detail, than the 2.5k lores icon. And the way that retina works on Macs is that those icons, menu items, buttons, etc in the user interface all remain that size even if you say switch to viewing your content, an image, at 1:1 (what we used to call "native" resolution). So, essentially, resolution-wise you get to have and eat your cake: more content at 1:1 on the screen without having to suffer tiny icons, text and other stuff like some of our unfortunate Windows using cousins. It's an amazing Apple feat, especially for photographers.
And obviously this works, since no one would be buying modern Apple stuff if it didn't, since it's all pretty much hires retina now across the product line. People swapped out old 2.5k iMacs for 5k new retina iMacs and didn't miss a beat.
