Like any other computer UI: Terminal-based programs (whether ultimately windowed in a GUI or not) didn't start off being familiar. But for those who use them, they eventually become familiar.

And that familiarity transfers between different systems. Windows, Mac, Linux, whatever: The flow of any particular terminal-based program is the same everywhere that it can be used.

It's tidy, and light. It's also network-transparent, and things like ssh keep it secure. Multi-user support is the norm instead of the exception on systems where terminals are common. It doesn't interrupt anyone else's work like something like using Anydesk to access some GUI desktop somewhere else can.

The keyboard shortcuts are annoying at first, but they're faster than mousing around in a GUI -- and once learned, they're approximately impossible to forget.

(You're free to hate terminals if you wish. I don't care if you justify it; I'm not your boss.)