intermediate tanks, wind loads will require certain designs (it could end up being a slendor depending on the aspect ratio) and/or damper(s) technology, etc. Lots of engineering problems that can be worked out (as they work out some in the video), but there is a limit on what makes sense rather than building several supertalls (like 800m) that are actually cool. Seems like these engineering challenges will increase costs geometrically comparatively to several buildings with the same space.