FR4GGL3: Nice find! I've never seen this back in the days. Today with all of those programmable Keyboards and HOTAS Systems it is not necessary anymore, but there are modern Button Boxes that follow this idea. If you have ever tried modern Combat Simulators like DCS you know that such hardware still has its use.
I absolutely love obscure vintage hardware like this and why I felt it needed to be documented. That particular unit went to The Strong National Museum of Play in Rochester, NY. They have one of the largest video game hardware/software collections on the planet. Worth a visit if you ever get a chance.
https://youtu.be/34Aernd6BdA