YouTube Post Type allows you to easily add YouTube videos as post into your WordPress installation via the introduction of register_post_type in WordPress v2.9. This will make YouTube a first class citizen in your WordPress.
Why would you want to do this? If you want a post to represent a YouTube video.
You add YouTube videos by specifying the URL or the YouTube id.
Your YouTube thumbnails are also downloaded and pulled into the system so you can use them. Your YouTube also gets associated to the first thumbnail found.
YouTube Post Type allows a WordPress post to represent a YouTube video via WordPress custom post types. This makes YouTube a first class citizen, and easily extensible by other plugins.
Shortcomings of other YouTube plugins: