Avatar vs. Human
I haven't interacted with avatars, so cannot base my opinion on personal experience, but I do get the experts' opinions and the results of research. While digging into this topic, I found several reports that showed we bring our own biases when we see people on videos: An actor might remind me of a former neighbor whom I strongly disliked, for example. OTOH, it could remind me of a good friend. An avatar is unlikely to provoke strong feelings either way, freeing a viewer's mind to listen only to the lessons or guidance.