I think it depends on your niche, I've not had any success with you tube ads, but like you've demonstrated they can work on the right site
I was thinking about signing up to it too. Put after looking at it decided against it. If I click on a clip on YT I watch it and move on most people want even remember what’s on the page just the clip they have watched. But with the Google ads most visitors glance at them. Although it is great for site content I just can not see any one getting many clicks out of it.