This plugin provides page optimisations for pages and posts which have embedded Youtube, Vimeo or Daily Motion videos which have been added using the core embed block.
Without this plugin, when using the core embed block, when your page loads, lots of external scripts and styles are loaded from the embed service, regardless of whether a visitor actually interacts with the embedded video.
This plugin prevents these scripts and styles from loading until the user actually interacts with the video. It does this by replacing the video embed, on page load with the video thumbnail image (added on Youtube, Vimeo or Daily Motion). When a user clicks the thumbnail the embedded video, along with associated scripts and styles are loaded.