Technically we do make light use of Google Docs as well, but mostly as shared permanent file storage, of which we don’t need a lot.
In general the goal is to make Discourse a viable team coordination tool, and that’s certainly how we use it!
Chat is the one exception, it is the Pixar Inside Out “short term memory” stuff which is decidedly real time / immediate / connected, and you actually want to forget most of what happens in chat every day. Only the long term core memories should be pushed into Discourse.