If you're going to criticise, at least provide him with more substantial feedback. A "no thank you" doesn't help him, but explaining why livestreaming isn't your cup of tea would be better.

If you think that no, you don't have the time to type out a full sentence like "sorry, I prefer screencasts that have fluff edited out" or "I prefer text because the information density is much higher", then maybe you should say nothing at all.