The instructions say: The video should contain nothing except the founders talking. No screenshots or postproduction wizardry please; we don't want this to turn into a video making contest. If you're going to spend time making something cool, put it into your demo/product.
However, I agree with you. I think people should strive to make a good first impression.
Beyond the bad quality of some of the videos, I was surprised how many people submitted videos saying words to the effect of "I have another co-founder but he couldn't be here for this video." If I were watching those and heard that, I'd automatically reject the applicant. If you can't even get your alleged co-founder together for a simple one minute video then things are obviously already falling apart.