I can't figure out if this is a step up or down from stuff like multiples and Lokiwives.
On one hand, they've probably made the best choice of stupid bullshit to believe way too much in. If otherkin or multiples were real and you were one, you now have either an unsolvable disorder or something that really looks like one. Godspouses don't exactly gravitate to good partners, so if they are real and you are one, you've entered into a terrible relationship with someone who you cannot escape from. But if djinn are real, and you have one? You've got basically a willing slave, and one that can grant you fantastic wishes. And since these djinn don't appear to be jerks that twist wishes, you're only ever coming out ahead on this one. Djinn-buddies won the Imaginary Friend Lottery.
On the other hand, this makes the question of 'okay, what really happened' that much more depressing. I remember at one point hearing someone (it must have been on Something Awful) theorizing that the super-religious, praying for everything types must have terrible self-esteem, and while I don't think he's necessarily right about them, his logic applies perfectly to these guys. There's a lot of satisfaction in the community, so clearly they're getting what they're wishing for, but realistically that only makes sense if they're wishing for attainable things. They've probably been wishing for things that are in their power: passing tests, getting raises/promotions, maybe love or friendship, stuff like that. You can pray, wish and hope all you want for those sorts of things, but ultimately it comes down to your own action and worth; you, in some way, have to earn it. People like this seem to remove all of their own agency for their successes, they're pinning something great that they ultimately did on something intangible rather than saying 'hey, you know what, I did good'. If all that's true, at least the religious guys have more to grab on to, these guys are pouring their everything into an overpriced rock they bought online. That woman who lost her djinn's stone seemed desperate, it read like someone's plea to get their spouse not to leave.
So yeah, it's kind of weird. It's a far more appealing thing to believe in, but they seem to be kind of worse for believing in it.