As I've noticed, you have to kill the nodes in order to "secure" the section of the station you are in and bring down the forcefields. Other than that, I don't think they do anything except provide target practice.
They who can give up essential liberty to obtain a little temporary safety, deserve neither liberty nor safety. - Benjamin Franklin
They serve no real purpose at this point. Though as someone mentioned, they do have an AoE effect that quickly stuns nearby Borg. But its really not worth the time especially if you're running an Elite. They do little more than draw your fire.
You do not have to kill them to "secure" the area and they will no longer spawn in Infected drones. We always ignore them.... with the exception of Brandon's node... don't see ya anymore ingame, B, so its how I says 'hello'!