Plain text and video both work exceptionally well in LearnDash courses. There’s no need to worry about device compatibility and video always expands to fill available device space. Adding video is as easy as pasting a URL from Vimeo, YouTube or Wistia into the WordPress Editor on its own line.
For free and open courses, YouTube is the easiest choice for including video. Vimeo is great for closed courses where permissions need to be restricted to your site and you want branding removed. Wistia is a great solution when more detailed analytics are needed.
Here’s an embedded YouTube video about the Uncanny LearnDash Toolkit: