Hmmm. I'm catching up on this too, since in the blog post I mentioned three things that Angie says are statements, not essentials. I can see the BCBG long black jacket as a statement, and the Everly booties (although in a broader sense, a black jacket and a black bootie would be essentials), but I would argue that the cropped Athleta capris are essentials and not statements -- they're black, unadorned, a simple shape (fluid and not overly baggy), and they don't fight with anything I wear them with.
The jacket and booties, to me are subtle statement pieces -- there's some detail and drama there, but the black keeps them from fighting with other statement pieces. I have other jackets that I would not want to wear with plaid pants, for example, because they're much stronger statements in terms of color and detailing.
This is interesting to think about. It makes me realize why, even though I owned black booties, I needed my black Ugg Cortona boots. Worn without the spats, they are very simple chelsea booties. Those would be essentials. My Fluevog flat booties are quirkier -- pointy toes, an unusual closure style, etc., and I tend to wear them with simpler outfits since they are a statement.
It seems to me that the more neutral in color and style an item is, with less texture, pattern, shine, or detail, the more it would qualify as an essential rather than a statement.