OLED displays have a different problem; they have so much noise at low brightness that the image falls apart. Still, I think a monochrome OLED display is what the person who wrote this article actually wants. It would have better performance in every respect to E-Ink, and it doesn't sound like their application requires E-Ink's low power.

My understanding too is that OLEDs can have "true black" pixels that emit no light at all. For "dark mode" style screens, this is a huge benefit, because the majority of the screen may simply be turned off. Conventional LCD screens still send current to each pixel, but the "black" is simply tuned to a dark frequency, rather than being altogether off.