The initial purpose for an HTML5 player is a consistent player look between browsers, as well as some additional functionality not built into the browsers' defa

The initial purpose for an HTML5 player is a consistent player look between browsers, as well as some additional functionality not built into the browsers' default players yet (e.g. full-window/fullscreen modes.) I imagine with time these libraries will expand to have a lot more of the functionality you can currently find in many flash video players.