Popular? Most of us hate it with a passion. Smartphones are the only reason anyone's making vertical video and only then because they're too lazy/dumb to rotate their device 90 degrees.
Vertical videos are comfortable to watch on a phone. Vertical videos are also great for capturing a single person in the frame, since people are also vertically proportioned.
>I suspect you are in the minority.
The reason landscape is the sensible choice is because our eyes are placed horizontally and our natural field of view is wider than it is tall. Portrait mode will be a good choice when humanity evolves to have one eye above the other.
You must be fun at parties.
Part of the magic of how vertical videos are shot is that the logical frame extends horizontally beyond the edge of the screen creating an overall larger picture which you can’t do vertically because people usually move horizontally.
If you are making programming videos to be viewed on desktop and somehow make it vertical people will hate you exponentially more.