User blog comment:Brandon Rhea/Intro to Wiki Modernization/@comment-80.229.116.230-20170309101516/@comment-13301-20170309103859

Since the video will be an advertisement, there's no point to make it editable. What they have on the Harry Potter wiki is (quoting) a test of a modernized video experience, the test is for video experience, not ad experience, so the final videos will be probably different from what they're now testing. Since this is still a test for a new ad format, I imagine they haven't contracted yet an ad network that deliver such advertisements