Sometimes teachers find great resources on YouTube and would love to just embed them into a post or assignment on their Bulletin Board as opposed to just linking to it.
It would be better to add this content directly what is being referred to instead of in a separate Embed area.
I tested this in assignments and you should be able to post your embed script from a youtube video into the assignment description using the source editor. It worked fine for me, let me know if you're referring to something else. Anywhere that you see source editor in the TinyMCE text editor you should be able to embed.