I've seen the retina displays of my colleagues, and while there's nothing bad about them, I don't really see the point. But I have rather bad eyesight and use huge fonts. I care more about the physical height of the screen in centimeters.

If anything, I would prefer to have more battery life and less memory usage than super-minuscule pixels.

I, for one, normally run my 15" laptop in 1600x900 mode when using on my lap (when using as a "desktop" I have two 32" screens at my desk), because of my old eyes, most of the Retina-lovers here must be the younger folks. I do like the feel/look of a Retina screen, but even when I borrowed a hi-res 4k laptop I had it set to something like 300% magnification.

Part of the point of using high dpi screens is that "native" resolution is not a necessity anymore to make it look sharp. I doubt it would be a good idea to run a 4k screen in true 4k if it meant everything became tiny and you needed a magnifying glass.

I think there may be some PC manufacturers doing this completely wrong. I've seen some Dells that are downright ridiculous. A high dpi computer should display large and readable fonts by default without any magnification. Look at any MacBook as an example.