Scouts are a DPS Class, that is what they do and the role they serve in combat. Point for Point, they are the best class by far at dealing damage to a single target. They were design this way, and poison is a critical part of this. If your not using a good poison, you are just an under-powered fighter that cant tank.
Any Scout can and should be using poisons. They serve a number of roles depending on what your doing, so make sure your using the right poison.
If your in an active group, you want a poison with a high direct damage on proc and a low damage over time componet.
If your solo and fighting higher level targets, you normaly want a poison with a low dd componet but high dot. Lets you deal damage during all those misses. ;)
When in a group, talk to the other rogues and figure out what they are using. Two poisons of the same color will not stack on a target. You may even wish to use a poison that deals no damage at all but lowers the enemies resist to attack types used by your group. :)
Note: Poisons work with duel weiled and with bows and throwing weapons. Nothing like a poisoned arrow from a ranger doing several hundred points of damage in the first few secounds of a fight. :)