I don't think that's true at all. I mean take Ramadan for example. Fasting until the sunset really makes you realize how the starving must feel. It gets you onto the level of people you've never even met, and it makes you rethink your values and basic human needs. It makes you feel grateful and lets you appreciate food and water instead of materialistic objects. When you look at it from "This experience can better me as a human being among other human beings" rather than "If I do all this maybe I'll get into heaven" then it benefits you a lot. Don't be so close minded to everything attributed to religion just because some of the religious interpret it in the wrong way. You can still be spiritual and an atheist.