Some services use WebRTC in a "hub and spoke" model rather than true peer-to-peer, and they often require VP8 due to a desire to support low-end Android devices that don't have hardware H.264 decoding.
I am surprised to hear that. Even $50 Android Phones now has H.264 hardware decoding support, what phones are those that doesn't come with it? And likely doesn't have VP8 hardware decoding either.
