Well typography is not really to look pretty but to explain things like what is important and what is less important. The Air speed and altitude is in a slightly larger font to show that it is indeed the most important of all the other text on the HUD.. however thats the only thing that is different in all of the text in all of the computer text in the plane. There is alot to typography including the negative space between words, letters, and paragraphs.
When a noob is confronted with a wall of text when he jumps in the a-10, there is nothing that jumps out at him in terms of hierarchy, guiding him to what things he needs to see immediately and what things he doesnt need to see right away. This was the biggest thing for me when i started. As i learned the systems, i saw alot of flaws in hierarchy of text and functions and how its positioned on the screen.