You misunderstand the video. A LCD controller must buffer at least one line, because the LCD matrix is updated line for line, all columns in parallel -- it's a matrix, much like a RAM matrix. However, the video just shows how the LCD is scanned out, it doesn't say anything about the buffering of the controller. A lot of non-gaming LCDs, and virtually all older non-gaming LCDs, buffer an entire frame, even if they are driven in their native mode.