The important thing about web components is that we _can_ import the component's script and then have new useful HTML tags.

You can drop this on a page and it _just works_:

    <script type="module" src="https://unpkg.com/chessboard-element?module"></script>
    <chess-board></chess-board>

And this is built with LitElement.

Live demo: https://jsbin.com/kicelemara/2/edit?html,output

Having dependencies doesn't change the external interface to an element, or prevent it from being drop-in. Dependencies are very often good, because they are well tested implementations of a common need, rather than ad hoc implementations that may be brittle or duplicative.