I haven't tried YouTube advertising till now, but definitely it will help to generate good traffic by promoting your business video. YouTube gets good traffic and ranking your video with rich keywords will help to get organic traffic for your website.
No, I guess it works if you're popular enough but I think generally it won't provide a whole lot of traffic. I would imagine (for me included), if you're on YouTube, you'll probably not go elsewhere to read things easily. You'll watch another video.
I did in my time of doing gaming videos, till I got so busy and real life started pooring into me I stopped. I tend to add all what is needed in the video information and then talk about it.