In addition to what you're saying, it can also be _harder_ to watch something at 1x speed. I've found that at 1.25x-1.5x my mind is more engaged. If it's too slow, I start thinking about other things and end up getting less from the video.
Some years ago when I used to play games there was these awesome guides to some hard challenges a guy made where he was speaking pretty fast because there was a lot to cover and it was narrated over live footage. It was perfectly understandable to me, but the comment section was full of complains about the speed and how it was too hard to follow. This to me suggests that most of people would prefer if you paused the action to make your point slowly and after that continued with the footage.