It's also from an era where you used one piece of software doing routine tasks that rarely changed.
Imagine learning all the keyboard shortcuts for every website you use nowadays.
For example I worked at a video store long ago that had some dos program to manage everything, I didn't own a computer and I didn't use any other software. It was still often a slow turd, and it wasn't networked with the 2 other local stores, so if I wanted to know if a customer had an account there, or if they had some stock there, I had to call.