I've always had a soft spot for cards that reveal hands and this card is pretty high up on that list. It's a little overcosted since it forces you to reveal your hand as well, but in the right control deck, that doesn't really matter. In a Grixis deck, for example, your opponent is going to be fairly certain that you will have both some kind of kill spell and some kind of counterspell in your hand 99% of the time, so what's the point in hiding it? The advantage then goes to you because now you know not to counter your opponent's Chalice of the Void and to save that counterspell for the Multani's Presence in their hand (because you're suddenly playing this in Legacy I guess). It removes all the guesswork that comes with playing a control deck without the issues of memorization that Duress-esque can cause. Finally, it can sort of work as a demoralization tactic against your opponent since they will probably start trying to overthink the game by making them wonder what plays you're going to make with the cards in your hand. It's subtle, but it can be enough to tilt some opponents. However, it is still a little overcosted and weak, but for what it does, I like it.
Pros: Reveals all hands
Cons: Overcosted, weak