This became more evident this weekend when Google added Video Sitemaps to Google Webmaster Tools' Lab section. On being clicked, it says:
“Video Sitemaps Errors. We are constantly updating our data, so please keep checking back with us to make sure your sitemaps are healthy.”
However the report is not adding any new information to the Sitemaps section in Webmaster Tools. And the most probable reason for this could be that the feature is so new and still features in Labs section.