We've been uploading videos as means of functionality proof for quite some time.
eBay does not take them as a proof and you can see why they wouldn't - they can't be certain what you upload is what customer had etc.
Videos are useful for those customers who are doubtful, but not actively trying to cheat.
Those who do try to cheat - and/or merely take advantage of the eBay rules that give them advantage over the seller - will not be convinced by videos.
And neither will be eBay.
