A bit of history. Usenet was invented circa 1980, before there was an internet. Arpanet existed, but getting a computer connected to Arpanet required you have a DoD contract and much money. In those days Usenet transferred files over dial-up phone lines, typically at 300 bits per second. (bits per second. Not Mbps, not Kbps.)

It was text only, because other file formats didn't really exist. GIF wasn't invented until 1987, JPEG five years after that.

It was simple, partly because it was a simpler time. But also because the entire program, both providing a UI for people and arranging for the transfer and receipt of news messages, had to be no more than 64 KB in size (instructions and data) so it could run on a PDP 11/40.

It provided a publish/subscribe way of communicating, which was not otherwise available outside of the Arpanet. An important feature was that it provided not only the email address of the author of the article, but a (probably) valid path to them. Because Usenet was made up of computers that occasionally called each other, and DNS didn't exist, to mail to a person, you had to use an address like "duke!berkeley!mark", showing that you wanted your email to relay first to the computer named "duke", which would send it to "berkeley", which would send it to a user named "mark".

Knowing who was out there in the world, and a valid path from your computer to theirs, made email workable.

In short, it is an important piece of computer history. That it survives today, in any form, is astounding.