Starts talking about LEDs and totally misses LCDs, which made heavy use of 7-segment displays and were ubiquitous for a few decades in the early years of consumer digital electronics.
Another interesting related technology is electromechanical vane display clocks: https://youtu.be/AradTqh0cuM . Each segment is shown (or sometimes obscured) mechanically!
https://www.youtube.com/watch?v=RTB5XhjbgZA&t=18s