I mean, if you accept natural selection as the driving force behind our evolution, it's pretty damn hard to assert that religion has no use, at least evolutionarily. At the very least, religion's positive effects must match the negatives (leading to genetic drift), and since the negatives are so readily available (as you'll find whenever you get into one of these debates), it follows that there must be quite a few positives.

The way I look at it is that religion likely developed in a manner similar to homosexuality. There's this theory in evolutionary biology called the "gay uncle" hypothesis that basically posits that relatively late in human evolution, when we had already formed tribes of some sort, some tribe or another happened to have (by way of mutation, crossing over, autc.) a few homosexual members. These members, since they had no children of their own, were able to contribute to the development of others' children, leading to greater success (2 parents + "gay uncle" > 2 parents) and therefore greater reproduction. So this tribe as a whole flourished, and the homosexual gene which was present in some members of the tribe with it.

As I see it, there's no reason religion couldn't have developed in a similar manner. Religion encourages people to be altruistic (generally), so people were altruistic towards those in close proximity to them (other members of their tribe), leading to a greater average standing and the spread of the religious gene. So that's my purely utilitarian explanation. As to whether religion is objectively a good phenomenon? I still haven't fully developed my own opinion on that matter.