Honest question: with multiple contributors or just a single individual editor? I’m building a word processor and never personally considered multi-player useful.
I've seen it done: group project where due to delays everyone needed to blitz through writing the report, four people hammering out stuff in a shared google doc. It works pretty damn well. You probably want to be in the same room or on a voice call with the others, though.
Multiple. Just writing down some stuff and comments at the same time you're writing the content is very powerful. For group projects it was the fastest way we found to get to a working plan as soon as possible and get to work on assigned parts of the doc. It's also nice seeing other people working at the same time as yourself
Similarly with Overleaf (an online Latex editor), where I've done group projects with up to 4 people simultaneously.
It works well enough that we occasionally used it for short chat conversations inside the document we were working on.
Uh yeah, it works amazingly well. I've done entire uni projects with Google Docs and it went great, and was much more convenient than whatever we did before using Google Docs