The question Matt Cutt’s addresses in this video is, “Does Google still need text for search engine optimization?”
The answer to the question is, “Yes.”
We could really stop this post right here. But I’ll go on a little further. Google still does not have the ability to perceive what is in image. Of course, if you optimize the image alt text, file name, title, etc, Google will be able to identify what is in that image. But Google wants to see more than this really, they also want to see text on the page. On any web page, it is important to have descriptive text if you want it to show up in the search engines.