I think it doesn't matter at all. If your copy is good, you can work something out even if your main strategy was to show a CB check. I think at the end of the day, it really depends on who is the buyer. If you are selling to random people with no IM exposure, the screenshot will be enough. If it's IM people who have been around for ages but made no money, that might have some negative impact - still why not make a video then? If it's seasoned IM people, then they are interested in different things altogether. If you feel this is the deal breaker, then video is the answer cause it's real hard to fake that (ie you log in to your CB, browse around, scroll around and show & comment stats).