I know my context here is different, but sharing my screen is an easy and quick way to show how to do something. I use discord constantly to show what setting to change, or what order mods should be in for friends, or how to set up that V rising server with the save file from last time, or how to fix that weird bug that my buddy describes and I immediately recall and know how to fix.

There are times a proper video or document are better, but I'd argue only when you're showing or teaching a process to a large number of people, over a spread out period of time, like a doc on how to set up your company email for new hires or something like that.

If its a short demo in a meeting for a simple process or temporary issue, its just a huge time saver to be able to just show people how to do it right then and there. Plus a screen share can be flexible enough to answer unexpected questions or issues that a static doc might not, like if tim has his start menu on the side, or mary doesn't have the right directx version installed and you gotta swerve to fix the edge cases. Hard with a static doc or premade vid, easy with a screen share.

If it can be explained in a premade video or a slideshow it probably doesn't need to be a meeting anyways. Just send it out and deal with issues as they arise.

Of course I come at the concept more from a basic IT perspective so ymmv, but for me its a very useful and flexible tool that can save me time and make explaining things much simpler.