Joining a group that believes in magical sky dwelling beings that grant eternal life in utopia provided you worship them enough isn’t the only path to community and purpose.

Yet I challenge you to find one more effective.

Whether by force/dogma or voluntary, a uniformly religious community connects at least weekly and includes all. Through this meeting, you get to know pretty much everybody, what they do, their families, their businesses. Which serves as a platform for making friends, finding partners, business opportunities, the like.

But it's one of many, and is one of the simplest ways to join a community as they are literally everywhere.

For the time/effort needed to join this community (plural), its pretty much free, maintenance isn't all that much either. People a few hundred years ago already did the hard part.

Not a bad deal. And all you have to do is suspend a little disbelief in something for a while.

It isn’t but we haven’t found another system that works as well yet. The delusion really gives purpose to life. We haven’t found another way to provide a comparable delusion.

The delusion is also a "costly signal" that you're committed to the group.

What do you mean by costly?

maybe, but it's still a pretty easy way to do it

Or it could be that a sky demon bestows blessings on the cultists who worship it. You never do know!