Though there was a story of one office that set everyone's sounds to classical instruments so things would sound like an orchestra tuning up.
- device connected
- device disconnected
But the sound effect support was never complete so some buttons and icons in Nautilus (the file manager) would make sounds when pressed but not those in the window manager. I think that is why they were dropped. Because if some buttons make a click sound when clicked but not others then the experience becomes confusing. And making all Linux desktop apps comply with the same sound effect "theme" (or whatever) would be very difficult. KDE apps would undoubtedly use different sound effects than GNOME apps and so on. It's a feature I sorely miss though.
I used my first computer in the early 80s so my answers can relate to a very different world/context than ours now.
First personal computer users had only experience with mechanical typewriters that made a lot of noise when typing. So 8bits computer keyboards usually have a feedback sound on each character. The sound was different in repeat mode and maybe backspace mode.
On input validation failure, systems usually made an annoying beep sound.
In the early mouse based GUI systems, the same kind of sound was used if you clicked outstide the current modal dialog box for example.
So sound was used as some kind of error signal mostly. On the mac the system beep was replaced with a duck sound (or whatever it was configurable).
Different sounds hinted the user if the message was some kind of error or an event notification. Until recently this may have an ergonomic value for some users.
PCs used plain system beep for a long time. These days the motherboards still use them as error message for things like missing RAM...
A good OS sound is instant and lets you know something important or different happened.
Funny.
This page has the files for the default system sounds for Win95. https://www.rjgeib.com/about-me/sounds/sounds95.html
You can see that there was a sound when the trash was emptied or when you receive a new mail.
This was really a different, simpler time. Imagine an open space where each computer make a sound each time you receive an email, even with a good spam filter...
In art, audio creates mood. An operating system isn't a piece of art to marvel at, it's the blank canvas upon which apps and games are painted. Those make the richest sounds to date!