Most people don't bother about video comments since most of them are by people who are promoting themselves and they're also very low on info density. You can read a paragraph in few seconds and it takes you minutes to get the same thing from a video comment. Video is perfect for teaching but I don't think it's great for quick bursts of communication.

I think video comments are going to be irrelevant in the long run. It's interesting to make a parallel with video phone. Video phone never took off because people didn't want to be bothered with checking how they look before they answer a phone. Fixing hair, shaving, etc... why bother with that?