Sure it can improve the broadcast. You know, the part where conversations aren't just about the spoken words but also about visual cues like gestures and facial expressions.
This isn't a problem with things like Skype or online gaming, why would a person need you to see them contemplate an answer to help engage with the audience? Answering questions, doing things the stream asks, back and forth joking with the stream, that's all engaging. Why is it "needed" to see the face they make when that happens?