The design on the left can look exactly like the one on the right if you turn those pixels to black (since the iPhone X has a first-ever-in-an-iPhone OLED display, black pixels don't radiate any light). I have not seen the iPhone X in person, but I'm assuming the blacks are so deep that the illusion would be quite convincing (this must be how it achieves its 1,000,000:1 contrast ratio). If you started with the full forehead design on the right however, you can't achieve the look on the left (because it would be manufactured with nothing there). In the existing design, the software gets to switch back and forth between these configurations, depending on the use case.
Even though the pixel area on either side of the notch is quite small, it seems disproportionally able to create the illusion of a larger screen (look at the image above once more).
Furthermore, Apple did something clever by making the areas on either side of the notch perform different swipe-down functions, something that would have been more difficult to achieve without them.
The iPhone X design is also slightly better at providing a reference point, both for identifying what orientation the phone should be held in, and also where to look so that FaceID can determine whether you're giving it your 'attention' (the technology will not unlock your phone unless it can tell you're actively looking at it).
The more nuanced criticism of the 'notch' design lies more in the fact that Apple itself seems to be advising app developers to always display the notch and to have applications work around it in sometimes-jarring ways. While that criticism is valid, I would say that—if problematic—the guidelines can still change, whereas shipped hardware cannot.