Known to some as "cryptic commands", "green screen commands", "entries", and "formats", we just call them "commands". We are sometimes asked why we teach commands when many of the Global Distribution Systems (GDS) offer graphical alternatives. The answer is simple: because operating a GDS with commands is the most elegant way of doing so. Commands are quick, convenient, and place no restriction on your preferred workflow.
Global Distribution Systems have been around since the 1960s. Over the years, airline pilots, flight attendants, reservation agents, and travel agents have all learned the commands and have used them in their jobs. There is absolutely no reason why a travel professional in 2018 shouldn't do the same.
If you drive a car with a manual transmission, cook your own food, sew your own clothes, are a fan of lightsabers in the Star Wars movies, or fly a Boeing airplane, you will be appreciate what it means to operate a GDS using commands. Even if you haven't tried these things, you will attain great satisfaction by learning and using a genuine skill.