Dragon Armor VS Daedric Armor Stats Comparison Video

Interesting, but ultimately irrelevant. Any armor past 567 displayed on your character screen does nothing to improve your actual damage mitigation. See the UESP article on Armor:Armor Cap.

Perhaps the most important bit of information on that page is the following:
"With the aid of enchanting (fortify smithing) and pre-made enchanting and smithing potions, and of course the appropriate armor perks, you can reach the armor cap with any style or type of armor in the game, even hide and iron armor. All without even using a shield."

Also, the reason the video shows Dragonplate to be superior is the set bonus perk. It only applies to worn armor, and only when you're wearing a matching set. He's wearing the Dragon Armor when he compares the two.