In my opinion, the most important kind of intelligence is the type of person who is always questioning things and deeply examines "both sides" of the story. Anyone who does that when it comes to religion, would have there bullshit radar going off.
Have you ever thought about the possibility that we know maybe 1/1,000,000 of everything the universe is? Bringing up an old cliche argument, if 500 years ago you said in the future we'll send men up to space in rockets, they would have thought you were a madman for claiming "godlike" powers such as that.
You can't possibly rule out the fact that maybe there is shit we have no clue about. Is there nothing after death? Maybe. We can't find out because we can't physically talk to anybody that has died. If I said '100 years from now, we'll be able to completely stop physical and mental aging, unlock our brains full potential, and discover exactly how the Universe is structured.' Sounds absurd. Maybe it will happen, maybe it won't. I can't prove that it will happen, but you can't prove that it won't - you can only prove that it isn't.
So what's the point and what argument could I possibly have using a bunch of "maybes" and "what ifs"...after all they're useless if you want to actually prove anything. The point (to me) is that while these things may not be true at all, they can help a person psychologically. Maybe if someone is going through a hard time and thinks God will be with them to get them through it, they'll have a more positive outlook on it. Hell, that's how it is with me. Sure there's a chance God might exist, but is it hurting me or anyone else to believe so? Nope, only helping.
The point is you can still be intelligent, think about both sides, and still sanely come to the conclusion that you do believe there's something greater than you out there.