Yeah, I sit up close to my 4k TV to use Google Earth Pro desktop and it is fantastic.
Same for looking at my photos. Looking at photos sitting close to a 4k display is just great, especially landscapes. With an OLED, it's better than slides in a projector ever were.
I also sit up close to play games, especially split-screen games. 1080 is noticeably lacking, 1440 is alright, but I would run 4k if my computer could keep up the framerate.
if you're sitting close and have a true high-res input, I doubt anybody would deny you can see the difference. But this is supposed to be a discussion about average people in their average livingrooms watching average content, so just ignore what's best for you and worry about average.