Good streamers (shoutout to Grubby) will actually read the question they're answering out loud before they answer it. Means I don't have to wade through the insane chat myself, but I still get to experience both sides of the Q&A when he picks out something funny or interesting to respond to.
Yeah for the most part that works, but I'm also often itching to give my own feedback to the streamer, and that is difficult to do without having it open :D
I will say, in the circles I move in, many content creators are also running a discord along side twitch. Some will even invite people into their voice chat to talk with them on stream.
I much prefer using discord in those situations, but that may be partly due to the higher barrier to participation that using discord immediately entails.