There are legit use for 8k video signals, but IMHO mostly on technical/niche fields. E.g. CCTV, drone camera will benefit greatly from higher resolution. Instead of having to pan/tilt/zoom, the camera can record the entire scene at once while still resolve enough interesting details. The end user just digitally magnify whatever part of scene to fill his screen if his screen is too small. Same technique can be use for zooming into say the goalie of a soccer game as the end viewer please.
I doubt layman would want to constantly zooming in/out all the time while watching soap opera though.