For 5 mana, Confiscation Coup gives you 4 energy counters as soon as it's cast. This means you don't have to store up energy to get good value out of it. Then, you can use it to steal something with a low mana cost and stock up on counters.
The overall consensus with this card was that it's fairly mediocre. But, the idea that you can steal a 4-drop on turn five is pretty decent. If you're already playing other cards that provide energy, a very good chance in this set, this gets even better. Keep in mind that you don't necessarily have to spend the full 4 energy this gives you to steal something.
Confiscation Coup was very solid in Limited, and proved somewhat playable in Standard in some Control decks. It all depends on what there is worth stealing indefinitely. While this is a bulk rare, it's one of the more interesting Control Magic variants that we've seen. Plus, it works into the energy counter plan about as well as anything. It's a solid little card in an Energy-based deck.