DFK - I didn't notice that the picture I posted was of someone writing upside-down. I assumed it was someone doing the intelligent thing I spent my entire childhood watching my left-handed mother doing, and flipping the notebook over to write "back-to-front" so the pages are right-side up but the spiral is on the opposite side.
Also, as Coro and I both pointed out, if you're writing on both sides of the pages instead of only on one side, your handedness doesn't matter because you're still going to have the same problem. Left-handed people will have the spiral in their way when writing on the right-side pages while right-handed people have the spiral in their way while writing on the left-side pages.
To put it another way, is this notebook a "righty" or a "lefty"?
Can't tell, can you?
"Left-handed" and "right-handed" spiral notebooks are identical except for the fact that the "front" and "back" covers are bound on opposite sides.
That means every person who has ever spent the extra money to get the "left-handed" notebook did so for purely aesthetic reasons.
There's no practical gain, there. It's a marketing gimmick that's no different than a gun manufacturer putting a pink stock on a gun, calling it "for women" and charging more money for it than for the standard model.