I have used it quite a few times. In terms of damage and farming, it is indeed weak. It is better than uhh... stun-stomp for farming. The power is the silence, mid and late game especially. Also, like a handful of skills, the affect happens before the cast animation; this means you can instantly interrupt; rather than waiting on a cast time (befuddle, soul burn, ect).
It is small things that add up. At max level, it is like a 90% silence time. With any other disable, or a WW, you can perma-silence someone. Perma silence is about equal to a max level vortex that doesnt drain your mana.
