No, not really. 4K@100% is 4x working space as 1080p. There's no way to put that much information in your field of view all at once. If you scale it up (or get really close) where anything is legible it goes out of your field of view and you can only look at (roughly) 1/3 sized region of the screen at a time. That's not usable as a single display. You're basically emulating multi-monitor 1080p at this point.

If you need more working space there's always 5K. That's 1440p@2x. You can even DIY one for pretty cheap. I know there's at least one 3:2 4K display on the market as well, though I wish there was a 24" version.

> That's not usable as a single display. You're basically emulating multi-monitor 1080p at this point.

That's a distinction that doesn't have to exist. If you don't insist on maximizing all windows, a single large monitor gives you more flexibility that multiple monitors with the same total screen area. E.g. for many applications 1080p is too wide to be effectively be used by a single window but too narrow to have two windows side by side. Dividing a 4K or screen by 3 is much better and also allows you to freely choose the window sizes. Some basic tiling support in your WM (either automatic or via shortcuts) is recommended ofc.

I use a 38" 3840x1600 monitor (= about 110 DPI) at 100% scaling and it works just fine for me at normal sitting distance. That's the same horizontal resolution as 4K and I don't think the missing 560 pixel rows would make much difference to how I would use it.

I use a 23.7" 4K (2160p) @ 200% and I think it's barely enough pixel density (180ppi), so I can't relate to this at all.

Apple's "retina 4K" LG Ultrafine 4K Display is actually 4096x2304 at this size, which is much higher density at 218.58 PPI.