Shake Shake Shake what?

I would like to begin by saying that I am a fan of the martinis. I am also a fan of the shaker and most anything that involves using a shaker. But I can't say that I understand the purpose of this so-called shaken iced coffee and tea and lemonade-tea at Starbucks. Does the shaking supposedly make it better? Also, isn't the purpose of using a shaker generally to chill a beverage that is then going to be served straight up as opposed to being used to chill a beverage and then pouring said beverage over ice? It hurts my head and also it breaks my soul.