> This will only disable webm VP8 + VP9, forcing FF to fallback to H264.

I'm glad you edited your comment but I'm still not sure what you disagree about. SoapSeller was talking about hardware acceleration and in that context disabling WebM globally will provide better performance/battery-life.

The only thing I was contributing to the discussion was the note that on Firefox this does not require an extension.

Correct. If your goal is the improved performance and battery-life, that's probably acceptable but it's definitely something to think about if you frequent sites which don't support H.264.