Traps is most useful for crowd control. Aside from the most useful aspect (the pull) traps set up a barrier that most mobs won't go through. So, you can use this to play a cat and mouse game and effectively kite at close range.

Also, traps can be used to inflict small damage. This is helpful when used in a combination with Clock and Nox. If the traps pull, and a sorc drops a Clock, you can use a charged Nox and create 3 separate DoT attacks. It's not a lot of damage, but every bit helps, especially when you spread the damage over a large cluster of mobs.


But, basically, traps are all about the crowd control...