I love the idea behind this functionality, however I hate how long it takes for video visual to resume when returning to a tab that's running videos. Please make this aspect of the functionality more responsive!
The issue lasts less than a second but is highly distracting to me. Often when I hear something interesting and return to the video, I'm immediately greeted with what looks like a frozen video player despite the audio still playing fine... and my immediate reaction to this is "**bleep**, did something bre- oh! It's doing that **bleep**ty thing again."