I started building this after a typo in one of my (otherwise perfectly valid) sites totally broke the layout in IE. With vldtr I now have an easier first line of defense against such breakage.

Another site I've inherited doesn't validate at all. It has lots of pages that I can now revalidate all at once after each deployment.

So indeed, the list is the main feature which distuingishes it from using the w3 validators directly. I'm considering more features, but I'm still thinking them through.