The pixelation is a result of viewing it a distance closer than the distance at which the image was designed to be viewed. At a microscopic level, a fine art photograph will show grain, an inkjet print will show ink dots, and a computer monitor will appear as individual pixels.
The video is shot in close and tangentially in order to show how it works.
By "pixelated appearence" I mean the blockiness caused by seeing the black sides of each block when its a different height. The display is a bit like a minecraft map with the colouring only on one face of each cube.
I agree. The opening scene of the video and the shot at around 0:38 depict the typical angles and viewing distance from which most people will experience the sign. From these view points, the individual pixels are not readily apparent. But a two video from typical angles and distances would not be very interesting compared to close ups that show the mechanism in action and showing the mechanism is probably more suitable for a sales/marketing video.
The video is shot in close and tangentially in order to show how it works.