4K for me as a developer means that I can have a couple of source files and a browser with the API documentation open at the same time. I reckon I could use legitimately use an 8K screen - get a terminal window or two open as well, keep an eye on builds and deployments while I'm working on a ticket.
Now yes - gaming and watching video at 8K. That's phenomenally niche, and very much a case of diminishing returns. But some of us have to work for a living as well, alas, and would like them pixels.