Cost of coffee in cup of latte is less than 25cents and Starbucks sells latte for $4.5. I am sure Starbucks has small price advantage compared to local coffee shop but this advantage is minuscule for widely traded commodities like coffee, milk and paper cups. I doubt that's their main competitor advantage.

Personally for me ability to order Starbucks coffee online and have it ready when I get to the store is a game changer + consistent user experience. Local coffee shops are always hit/miss.