This one is easier and more universal than the other approaches. There's not setup involved like: $("#foo").myWidget(); You just put the markup on the page

This one is easier and more universal than the other approaches. There's not setup involved like: $("#foo").myWidget(); You just put the markup on the page and include the JavaScript: <my-widget></my-widget> And of course, you could do querySelector before that existed but that doesn't mean there wasn't benefit to it being native.