Back in the day, the majority of tools available used a command-line interface. As npub1k9arkn78gmdp5ew20r44aqwwu84wjhvshjf9kcht46heh4zajthsjjm3yh (npub1k9a…m3yh) previously pointed out, IRC was a very simple, light-weight and scalable means of communication at a time when the internet was still in its infancy.
These days IRC is nothing more than a novelty from a time long past, but you'll be surprised as to how useful having a command-line tool for something like posting to the Fediverse for example can be to the ten system administrators or hobbyists that use them.