8k is quite good for acquisition as you can zoom in in post and not lose quality.
Certainly in the uk it's useless for transmission yes - based on actual screen sizes, ideal sizes, and living room sizes, even 4K is meaningless to those with 20/20 vision for a typical broadcast (for computing panels it's another story). I was at a SMPTE event a few months back where they basically said 'we know 4K is pointless, but the panel manufacturers want to sell new TVs'. In the last 20 years I think we've gone from 4:3 to widescreen, flat screen 720, flat 1080 (full hd), 3d, curved, 4k, 4k hdr -- a new type of technology every 3 years.
I remember the first time I saw the NHK 120fps stuff, I was blown away by the clarity of moving text when compared to the same signal at 60p.
