Smokey is not the enemy by Hitta

From events, it appears as if Smokey is contained on the island. It requires a certain compass bearing to leave. He was probably bound to the cabin through some sort of special ash. The island could be some sort of prison. Ironically with it being possibly a prison system, Smokey's plan for escape involved John Locke, after the season 5 finale, Smokey was being referred to as "Unlocke".

Ben once controlled the smoke monster to kill the attackers on the island after they killed his daughter. He and Rosseau also referred to Smokey as the island's "security system". Smokey was possibly under the Others/Jacob's control against his will. It being called the "Security System", I think the greatest threat to the island isn't Smokey but some other figure which hasn't shown himself yet, or hows identity hasn't evolved into the spotlight. Jacob needed Smokey, because of the third party threat got its way there would be catastrophic damage of epic proportions. Smokey isn't really evil as being Lost's end of all end baddies, he is more like a neutral party caught up in something against his will and he just wants to "go home". Smokey used Locke and Ben to carry out the assassination of his taskmaster Jacob. Smokey found his loophole around the chains of his master Jacob, by getting rid of Jacob completely. Jacob had a final plan though. He had to convince Smokey! that everything(the island or possibly the world) was worth saving. This is where the survivors of Oceanic 815 come in. Jacob's plan is to prove Smokey wrong. Before Jacob died, Jacob told Smokey that "they are coming". It wasn't to throw it in his face, or to show that he lost, but to warn him and tell him that his fears were coming true. Jacob didn't care if he died, he would die willingly for the cause. Smokey never believed in the human condition and the evolution of humanity, his goal wasn't to destroy it but a position of apathy. Jacob is trying another tactic, the plight and compassion of the survivors.