"Nobody" is obviously the market that RED is targeting with their 8K cameras (shooting raw/lossless for that matter) or various projector manufactures. Sure not everyone in the production pipeline is going to be watching manipulating the edit list in 8k, but you better be sure there are a few people looking at the dailies at full 8k res before the OCD/dictatorial director shows up.

Apple obviously thinks there is a market here too, or they wouldn't be talking about how the machine can show three simultaneous 8k streams.

Yes I do edit 12M images on a ~15M monitor. Its also the weak point in the system, as your average midrange+ DSLR is 25-50M, and its pretty easy to create a printout where the effective resolution of the page/poster is vastly higher.

But that is not really the point, the apple presentation goes on about how the machine can play 3 8k video streams simultaneously, but you have to buy a 3rd party monitor/projector to even be able to view a single stream.