I question whether 4K on the average laptop screen size is worth the added load on the GPU (and so, lowered everyday performance and battery longevity). On big screens, sure, but at 13 inches? At that point you're stretching the limits of perceptibility, and given the other compromises you're already making to have a laptop instead of a desktop, it seems like a doubly silly one to add.
Well, my current laptop, a Dell XPS 13 has a resolution of 3840x2400 and its great! Yes, my normal use, I have things scaled/zoomed but for watching videos, its fantastic.
For normal use, 1440p is fine, but 1080p is too low for me. 4K is probably not necessary if its only used to watch videos. I probably should have flipped it and said: "give me 1440p, or even 4K"
Although one area where I find higher resolution is beneficial code editors, if I have enough pixels that I can have 3 vertical splits and have the text still look crisp, that really helps my development workflow.
On a 15" and above though, I wouldn't go lower than 4K personally.
