RAW video at 8k60 ... if that is in the plans, a TB won't be enough. I'd want a couple uSD card slots. Heck, I'm even filling up my 128G limit shooting standard 4k30 H264.
But seriously, who owns hardware sufficient to play 8k60, let alone edit it efficiently? Then comes the question of who is the audience? 4k hasn't really reached maturity yet (how many people actually pay for 4k content or know it when they see it). 8k60 is early adopter at best. Only a few TVs even handle it - they are all spendy. Of course that won't affect folk who just buy for numbers.
The advantages of 8K shooting are almost entirely separate from the hypothetical scenario of viewing 8K footage on an 8K TV or being enticed by 'marketing numbers', especially since most people cannot even distinguish the difference between 4K and 1080P on common existing TV sizes (it becomes much more noticeable to the average person in projector setups).
Just to list a few reasons you might want to shoot in 8K even without any means of viewing native 8K content:
1) Huge leeway for lossless cropping/panning/zooming if your end goal is 4K output (or anything below 8K). You can worry about composition after the fact and have a huge buffer for making mistakes.
2) The ability to grab ~33MP stills from any frame within your footage which is more than enough for a large print
3) 8K down-sampled to 4K will result in higher quality image than native 4K
4) Higher resolution gives higher color fidelity and better gradients
Programs like DaVinci Resolve allow proxy editing, so you don't need a computer capable of editing 8K footage in real time to edit 8K. You can do all your post processing work at 1080P or 4K if you wish, even with an 8K final output.
The largest downside to filming in 8K is storage, which is for the most part dirt cheap these days anyway, especially relative to what will probably be a $3,000+ drone.
Of course it still won't appeal to everyone, for example those just wanting to take fun videos and edit them on their iPad or whatever, but shooting 8K really opens a lot of doors.
All the same points above also apply (proportionately) to shooting 4K if comparing to 1080P, and will apply to a hypothetical 16K vs 8K scenario some time in the future. Just like with stills photography, more resolution is always better strictly from an image quality standpoint,
all else being equal.