The arrangement makes more sense to me than having two monitors side-by-side. And LG notes that it "reduces side-to-side head movements, the main cause of neck pain."
Computer accessory manufacturer Mobile Pixels reckons their take on this is even more ergonomic than LG's. Their forthcoming Geminos is another two-in-one monitor, but theirs is hinged in the middle, allowing you to dial in the angles.
"Simply adjust the two 24-inch displays based on your height and working position (sitting or standing) to achieve a healthy, ergonomic alignment during your work day," they write. "Geminos is infinitely adjustable, unlike other dual desktop monitors. The top monitor slides up and down, and the bottom monitor pivots in and out to create a bent visual appearance surface."