What is the significance of argos’ death and why might homer have included it in this poem?

Argos was Odysseus' faithful and loyal hunting dog. Argos waited for Odysseus to come home. Argos started aging for all those years that Odysseus was gone for. Argos was the first to recognize Odysseus' arrival at Ithaca. When Argos first say Odysseus in a very long time he tried to wag his tail. Argos was fulfilled with seeing his master. He whimpered and died. 
Odysseus didn't get the chance to spend time with his dog because he had to go to the battle of Troy. Men would hunt wild goats and rabbits with their dogs. Argos lived outside of Odysseus palace on a heap of manure. He was also covered with fleas. When Odysseus sees Argos he wipes away a tear casually so Eumaeus would notice that the old beggar was Odysseus. Odysseus tells Eumaeus that its is strange that this dog does not have strength or speed and out here lying in a pile of dung. Eumaeus replies that Argos belonged to a man who died a long time ago at Troy. He says if he took care of the dog like Odysseus did he would be in shape. His dog is in the story because Argos resembles loyalty and companionship.