Well, for starters, having religion gives you a rational basis for moral behavior, a meaning to your life, and a validity to human reason. And those are just the benefits you get from religion even if it’s NOT true.
If it IS true, then the benefits increase exponentially: it can get you right with God, heal a damaged soul, give you a glorious and pleasant afterlife, afford you wisdom, grant you blessings, etcetera, etcetera.
Regarding it’s benefits even when it is NOT true, it kind of requires some weird mental acrobatics to go on doing normal human things without a religious context. Even if religion isn’t true, human minds seem to be built with an innate need for it in order to make sense of most of our own behavior. You could even say it is more in accord with our nature to have religion, even if it is not true. It’s a statistical fact that suffering causes more people to be religious than otherwise. Of course, there will always be some who are so intellectually secure in their atheism that even suffering doesn’t touch their lack of faith, but, generally speaking, even in countries with higher tendencies toward atheism, when some disaster happens that causes a lot of suffering, those affected tend to become more religious than they were before. There’s almost an impression that it is a survival mechanism to provide motivation to keep on keeping on since the only logical thing to do if your suffering is meaningless and you can’t escape it is to just off yourself.
I once saw a pretentious atheistic meme that was attempting to “clear up” religious misunderstanding of nihilism. In one half, it showed your stereotypical depiction of nihilism with the caption “nothing matters” and a depressed looking person with their head in their hands, despairing. The next half showed a bunch of people partying as if they had not a care in the world since “nothing matters.” The point was supposed to be that nihilism ultimately brings you joy, but there is a critical problem with the meme, and it is so obvious that I’m surprised the meme even made it into existence. For the starving child in Africa with no hope of survival, the positive interpretation of nihilism doesn’t apply AT ALL.