no, even if you download movies/music videos/tv shows from the iTunes store it wont let you use cover flow for videos =[ i don't know why, it s really stupid that they don't let you. probably because not many ppl will have to many videos, and even so, the ppl hat have the most videos cant have too many videos since we don't have that much storage space. i think Apple intended cover flow to be for things that have a lot of files to choose from. but then again the iPhone doesn't do a lot of small things that it should do.
That is intentional. The iPhone is treating the video as a song. If you look for any music video, it is always listed not only in the videos section, but also allong with that bands music in your iPod. So if you select that song title under the bands music, it will always just play the audio only and this is why it shows up in coverflow, because it is just the audio. The video will only play when selecting the video through the video section of the iPod.