[Snake]

If the trap triggered when the enemy hit the center of it, the entangle vines would have more use, as the opponent would be surrounded by them. And they would be halving the attempts to escape by move. Or having to resort to movement skills/spells.
When the trap triggers, the enemy stops on the border and the pull towards the center is interrupted, so the opponent can just walk away of it without a problem.

I'm saying in a situation where the Archer places his trap at north, then uses pulling shot from south at an opponent infront of him. They get pulled all the way to the north trap and 'jailed' there in the middle of a vine 'explosion'. As the trap will only trigger when pulling shot finishes dragging them to the middle of the trap's zone. (In this case, on where the trap's been set).

That's how I ever thought this neat-looking combo would work, in my opinion.