Are LCD screens driven on a pixel by pixel basis, or is the entire screen driven on each refresh? Because the article says they're only causing changed pixels to refresh.

If so, you're probably still right when it comes to watching a video or something, but e-ink could be more efficient for drawing, writing, or reading.

IIUC, display controllers normally iterate rows and columns like a double for loop. The outer loop increments the row counter, inner one increments the column, and the voltage meets at the current pixel at pixels[i * j]. Most LCD controllers don't take pixel(i, j) or pixel[i * j] as the input, but expects a synchronize() signal to reset both counters followed by transfers of either row[width] in rows[height] or pixels[width * height].

The bare panel, for both LCD and EPD, would consist of a pair of glasses vapor coated with transparent indium tin oxide, chemically etched as bunch of horizontal lines on the first one and vertical in the other one, with corresponding choice of fluids suspended inbetween. It would be possible to wire a custom fabricated controller onto those row and column electrodes to drive individual pixels. I guess that is what is being done here.