I don't like knowing what's going to happen on rides, i like them to be a surprise.
Obviously if you know the layout you'd be wondering 'how can you be surprised if you know what will happen?' Then meh, personal preference.
Don't get me wrong, i watch them, but only if i've ridden the ride and wonder how the POV would look [aka i rarely EVER watch coaster POVs, mainly of flat rides].