When the Deadlock Trap enters the battlefield, it comes into play tapped. However, in the process, it gives you 2 energy counters. Each activation of the Deadlock Trap takes one energy counter. People have argued, why not have this ability use mana instead? I'm actually quite certain that the only reason this card exists is because of energy counters. There are enough ways to generate energy in Kaladesh that this card is actually probably better than it looks on the surface. It's also clear that there are going to be a lot of planeswalkers between Kaladesh and Aether Revolt. It seemed probably more useful in Kaladesh Standard than it would be in a vacuum.
In the long run, though, this card is more of a curiosity than anything else and a bulk rare. But from a control perspective, Deadlock Trap is an interesting card for casual players to consider. Three mana for two activations of this card is actually well worth it, but it's slow. At the very least, it's a cool collector's card and it will slow down an opponent in the right setting.