Usually, your opponent's cards are not going to help you much, outside of being extremely sacky and drawing your opponent's Dark Hole/TT for them. Still, this does give you two cards, for whatever discarding purposes or bluffs you may want. It could see some play in a silly Deck or in a Deck where the player intentionally "forgets" to give the cards back after the duel, but it still won't be all that useful.