If you're in a situation where you don't want to Death Grip, and you're not in melee range...
You have the choice of sitting there with full runic power, or using it.

A great example will be holding a bunker in AV.
I position my guys around the donut ring (at the top).
Each with their back to a pillar, so they cannot be blown off of the edge and out of the bunker.
They are facing different directions (all inwards), so if any one is engaged they can either all engage, or all but one if the attacker moves behind the active toon.

IWT is disabled, because if it is enabled they will run off of the edge (towards the attacker) and fall down the stairs on the inside... at which point they die as I regroup them.

Death Grip is useless, because it brings the target to me, while I want to kill it as it moves up the stairs.
Similarly Frost Strike is at most going to be applied by one DK and not the others.

As you may note, Frost Strike is higher up in the priority than Death Coil.
Which means if a Frost Strike can go off, it will.. and not a Death Coil.

So what's better...
a) Use Death Coil, when Death Grip/Frost Strike aren't practical; or
b) Sit on your runic power and do nothing with it?