This same idea carries over to video as well, where it actually expands a little. Not every performance on every given night is going to be perfect. In the live music settings, strings break, wrong notes are played, sound gets wonky, and a whole assortment of other things tends to happen. That's the nature of the beast. When people start recording video of every show on their nice cameras, those mistakes get preserved and broadcast. Not only that, but they're presented out of context for others to watch online. Maybe the drummer breaks a snare drum head in the middle of a song, or the guitarist gets the neck of his guitar whacked, throwing things out of tune. That might not come across in a Youtube video presented on its own, and that makes the artist look bad.