I would suggest also posting a short/abbreviated (textual) answer. If I came across an answer that was simply a YouTube video, I would skip by the answer rather than upvoting. (This is not to say I wouldn't watch the video if I asked the question--rather, if I didn't ask the question, but just stumbled upon it.)
I tend not to watch random videos. It takes longer for me to determine if a video is good/incredible (versus a total waste of my time) than to determine if a textual response is good.
That said: if there was a clear textual response that I liked, and it closed by saying, "I've explained this in [a more clear fashion]/[more detail]/[a graphical way]/[etc.] in this video (link)," I would probably follow the video link.
tl;dr: A video link by itself wouldn't attract my attention. However, if accompanied by a short/barebones answer, I would be much more interested.