Because wordpress makes it easy to embed a video.

Find a video on Youtube or vimeo.

Copy it’s URL, or web address.

In my wordpress blog editor, just put that URL on an empty line, all alone (not as a hyperlink), e.g.

https://www.youtube.com/watch?v=1CLVgJ7yoXc

And voila! It is embedded

Video in your page, mmmmmm good.