This is pretty weird; I have never seen a design like this, and would have taken it for a joke (or a modern architect's exhibit) unless it isn't advertised in Suumo.
Let me take there chance to describe the state in normal Japanese apartments, though.
Usually, Japanese like their toilets to be separate. Unit baths where toilet seats and bathrooms are combined are not popular here. Besides, I know at least a few Japanese people who complained about toilets being too spacious. Usually they are very small. And they are always equipped with an exhaust fan. I wonder how this even got approved. You basically can't have a visitor, and the air conditioner will scent the room :-p.
The only thing that is close to this that I have seen, are the toilets in the International Student Housing (single) in Odaiba. The top half of the toilet walls are made of glass, but at least there are curtains inside that you can close. We used to joke that they are built that way to discourage the Chinese students who often shared or sub-let the apartments.