Embedding vs Linking
When you're trying to bring in content from another source, you've got a few things to consider: should you embed, or should you link it? If you link it, should it be an external link? Internal? Which is best for what situation?
The answer, as with just about any rhetorical question in this Style Guide, is to consider your audience and what you expect them to do with the content you're trying to share.
For example: you know that embedding content allows the visitor to play the content from within the page itself. But consider: videos are always accompanied by a thumbnail of some kind. There's always some kind of still preview before anybody clicks play. Does that thumbnail clash with the rest of the information you're laying out on the page? Does it contain objectionable material? Or, going further than that, are you perhaps just linking the video as a kind of throwaway joke? Then maybe... just maybe... you don't need to embed it!
At that point, hardlinking it via the rich text field's Link feature might be the best idea.
As you may or may not know from training, "internal links" are links to pages we host here on https://portal.cca.edu. What you may not know is that when you opt to use an internal link instead of an external link is that Wagtail updates those links automatically if those pages happen to move (which they are liable to, given the dynamic, fluid nature of Portal development).