This page has a video as a hero background instead of an image (may not load on mobile phones to prevent using your data).
Videos are a powerful way to draw visitors into your content.
For the videos, you can host them yourself here in WordPress, with a service like Amazon S3, or use a YouTube video.
The featured image will also be the «poster» image of the video. It appears before the browser has loaded enough of the video to play. Often this will be a still of the first frame of the video to make that transition smooth.