In my opinion, now it is doubtful they are included because it would be more complex (and from what we know, they want to stay out of too much complexity
)...
But if they were in, it might have something to do when zooming all the way in, because I do think that this screenshot is not zoomed all the way.
I'm not a game designer, obviously, but all I can do is speculating.
Either they included multiple squares, or mixed terrain which would make the whole landscape more natural. One more thing I noticed is that when you look at the bottom-left square, there is a green strip all the way through it, with plains on the side. And again, I assume it is all one square (look at edited pic on post 10).

But if they were in, it might have something to do when zooming all the way in, because I do think that this screenshot is not zoomed all the way.
I'm not a game designer, obviously, but all I can do is speculating.
Either they included multiple squares, or mixed terrain which would make the whole landscape more natural. One more thing I noticed is that when you look at the bottom-left square, there is a green strip all the way through it, with plains on the side. And again, I assume it is all one square (look at edited pic on post 10).