Religious faith in a comic book world takes on a completely different meaning than it does in the real world.  In the real world faith reflects the belief in an all powerful deity (or deities) who are intrinsically involved in the affairs of man without directly revealing themselves.  Faith in comic book worlds takes on many different aspects.   In comic book worlds gods do directly reveal themselves, including what many consider to be the Christian God, and characters venturing to heaven and hell is not entirely uncommon.  Despite the presence of the all-powerful there are still a hand full of characters who are firmly either atheist, or believe that there is a scientific explanation for all things.  Somewhat stereotypically compared to the real world, these characters are usually the most advanced scientists or engineers (Iron Man and Mr. Terrific.)  These characters nonetheless adhere to their beliefs.   I am not sure if this is a viable option in their worlds, in that they become the opposite what real world scientists adhere to, their faith rests in science and not in religion, and they expect the great unknown to be explained by science rather than divinity.  

            In terms of real world applicability though, faith in religion would be harder to substantiate.   Many people in the modern world try to comprehend the suffering of others through religion and either come up without an answer or chalk it up to God’s great plan.   This leaves the actions of rapists and murderers somewhat ambiguous in terms of their relevance to faith.   What therefore in world where God and the gods have revealed themselves?   Would these deities not therefore become objects of scorn.   Regarding the amazons and Wonder Woman, they place absolute faith in their deities and despite being the only large group of people left in the world, they are treated as nothing against the whims of the gods, being pitted against one another, ignored, abandoned and subjugated.   In light of faith does knowing that God or the gods are actually there actually help?   Or would it shake the whole set of beliefs?   It may or may not, after all a lot of people believe absolutely in the presence of gods anyway, so a physical manifestation of their presence might not affect their perception, but from a practical standpoint it would probably debase somewhat their following.  Some aspects of prayer are somewhat egocentric and probably beyond the capacity of gods to answer (prayer for success in an endeavour for instance) but real prayers which went unanswered (matters of life and death) would likely cause more consternation with the all-powerful.

            There are certainly other aspects of this question present in comics.  For instance in the story arc For Tomorrow where Superman takes Father Daniel Leone as his spiritual adviser (would a spiritual adviser be necessary when someone has been to heaven?).  These two though I think are the two most touched on in comics and one which like religion itself, is usually left ambiguous.