I'm not in construction, but one reason could be because it's easier to deliver large items, supplies, and heavy equipment to a given floor when there aren't any windows in the way.
I remember everyone joking about @Benito passing coffee over when they reached eye level. Can't believe that day is here. I also can't believe the building is only a third of its (requested) height.
These are going to be amazing buildings, but I still wish they'd stuck with the 2013 cladding, even with only the two buildings. That would've been an absolute standout.