How does the metaphor of the rattrap serve to highlight the human predicament?

The peddler, thinking of his rattraps, considered that the whole world was nothing but a big rattrap. Its only purpose was to set baits for people. It offered riches and joys, shelter and food, heat, and clothing, exactly as the rattrap offered cheese and pork, and as soon as one lets oneself be tempted by the bait, it closed in, bringing everything to an end. After the peddler stole the crofter's money, he lost his way in the forest. Then, once again, he thought about the world and the rattrap. It was trapping him now. He had let himself be fooled by a temptation and had been caught. The forest, with its undergrowth, closed in upon him like a prison from which he could never escape. The peddler also told the ironmaster that the whole world was nothing but a big rattrap. All the good things that were offered were nothing but cheese rind and bits of pork, set out to drag people into trouble. None escaped one person Jails into the trap one day and the other the next day. The metaphor of the rattrap highlight the human predicament when in the end, the peddler left the rattrap as a Christmas present and wrote in his letter which is for Elda considering himself as rat and said that this present was from a rat that would have been caught in this world's rattrap had he not been treated respectfully and kindly as a captain.