Australia is such a large country-continent that any technology that helps to shrink the distance is hailed as a marvel. The Overland Telegraph really was.
There’s a good history of it, here, that includes the camel trains that supplied the workers and the history of telegraphy in general.
Telegrams delivered way too much bad news over the hundred or so years in which they dominated fast, distant communication. I could just cry when I read how people dreaded the sight of telegram/messenger boys during the wars. But it wasn’t all bad news. Telegrams could convey and record happy events — births, marriages, climbing Mt Everest, whatever.
You can still send telegrams, today. It seems a weird amalgam of old and new technologies, but you can use email to send a telegram through services such as Telegram Stop.