The first and third links above, I used https, but they were automatically changed to http.
The second and fourth links above, I used http, but this gives an error.
The website CMS is modifying the code. When I use https, it automatically is changing it to http. However, when I use http it is apparently retrieving an error video from Youtube.
The advantage of the "Share" link supplied by Youtube videos is that it only puts a link. It does not try to embed the video. A thread with lots of embedded videos can be difficult for some browsers to manage. It takes more resources.