In ancient times, the best way to get people to come together and follow or support you was to give them a common cause or a common identity. And that was how religion and tribalism came into being. It continues to this day. Whether God exists is debatable, but as someone said, faith in God sure is a real thing with real consequences. I still do not know exactly how(would like to research more on the neuroscience of religion), but having faith in any entity whether God / religion/ a guru/ a person whom you explicitly trust changes the physiological functioning of your brain. It changes the way you think and act. Even if some were to consider it a crutch, for many others it is literally life altering.