What the post says makes sense if you assume that it's an entirely cosmetic change, which it's not.

YMMV on the styles (I'm undecided on them), but there's a ton of stuff under the hood that just couldn't be slapped into the desktop, without huge drawbacks or compromises. In the second section the post kind of recognizes this saying they're doing it because "the world is going mobile"/low power, but then immediately goes on with "It's change simply for the sake of change", and I don't think it can be both. Simple squares, non-overlapping windows and text rather than (pixel shader'd) graphics aren't just an aesthetic thing, there's a fair amount of practicality in there.