My guess is - to fit within the bounds of the space allocated within the cockpit dashboard - to fit enough information on the screen so the end result isn't c

My guess is - to fit within the bounds of the space allocated within the cockpit dashboard - to fit enough information on the screen so the end result isn't cramped - to possibly take advantage of an existing CRT assembly that already existed somewhere in the world, so they weren't commissioning a custom design (and the tooling required)