I think the problem is that not only does it take a ridiculous amount of life, it also has no start up animation at all. And let's also put in the fact that it is an automatic guard crush even with a full GC meter. When you factor that in, you can see why someone would just want to stand around and spam it whenever they can.
And even if they miss the attack, you have to be quick to get to Raiden because the move sends him across the screen it seems.