What is the purpose of omens in The Alchemist?

I think that the purpose of the omens was to guide Santiago. Every omen that Santiago saw meant something important. They all guided him along the right path to completing his Personal Legend and finding his treasure. For example the omen of the two Hawks at the oasis, he sees the Hawks and knows that they are signs that a war is coming. Once he believed in that omen and told everyone it set off a chain of events that led him to his Personal Legend. Everything is connected. One decision sets off a chain of events to the end.