"When you get down to it, physics engines are really just a way to make the things that don't matter in a game look extra pretty. Unless you're the kind of gamer who actively looks for it, you're not going to be paying attention to the realistic way the curtains waft in the breeze while you dive through them firing madly at your enemies."
Did you... did you really just say that? Because this is the first physics engine I've seen that has the potential for truly destructible terrain (Red Faction tries, but it's not there). Like, I just dug my own foxhole. I cut a small hole in this wall and spied on you. I knocked down the building you were in by carefully placing grenades. Sure, some games have SIMULATIONS of this happening (it's your mission to place these grenades under the supports of that building), and some games have limited destructible terrain (shoot that wall and some of it MAGICALLY DISAPPEARS), but this kind of physics engine allows you to take down buildings not because it's specifically programmed into the game for you to take down that building, but BECAUSE YOU WANT TO.
Pirate games got a whole lot more interesting, too. Your ship does not have hit points: your ship is a ship. BANG! Now there's a hole in it. Depending on where that hole is (below waterline? Uh oh...), you could have a major problem on your hands, or it could be merely cosmetic.
Just using the curtain examples, think about stealth gameplay. You're in the dictator's office, looking for evidence of nefarious activities. Suddenly, you hear a key in the door. Do you press a button and enter "stealth mode"? Do you walk THROUGH some curtains and be instantly hid? No. You push aside the curtains as quickly as you can and get behind them. Unfortunately, you're a bit too wide for the space, and your outline is faintly visible through the curtains. Hope they don't notice. This would be amazing in multiplayer, since the other person would have to actually be paying attention to notice you there (instead of the computational equivalent of a spot check for an NPC).