If you combine the energy costs of delivering streaming video and the client side costs of playing video and executing JavaScript I have no doubt porn far outstrips Bitcoin. Hell, I bet JavaScript bloat from adtech alone and exceeds the totally energy budget of France.
It takes about 30 W to watch video in a browser [1].
Assuming every internet user watches 85 minutes of video per day [2] (517 hr/year), video consumption is 52 TWh per year. Or less than half of than the bitcoin network.
Google uses 12 TWh per year [3]. Assuming Google is entirely focused on serving the world's video (it likely could), that still is ~half of the bitcoin network.
