I don't think that we really need to gamble because gambling doesn't really give our basic necessity. Gambling is just for fun, to relax, but for others it is something different because they become addicted to it. But if you will learn to control yourself when to start and when to stop it means you can live without gambling.
So it means that you will gamble because you want to relax your day from a exhausting day from work or anything, gambling for your self is for relaxation and for fun. Though i do agree with you that some of the people are addicted to it and sort of getting addicted to it that makes their whole life and cant make their day without playing it and the worst is cant sleep just to play gambling games and a lot of debts.
Still there are also those lucky one that is really getting a lot of profit from gambling. I have a lot of friends that is used to play gambling games, dice games and end up winning big amount of money but i do try in my self i keep on loosing.