For millions of people to be helped by Him, He needs to exist (obviously).
This is not so. A mere thought can move mountains, so to speak.
For instance, I can make a simple statement saying "Mentat, you must brush your teeth 10 times a day. If you do not, I'll use my l33t h4x0r sk33lz and track you down, come to your house and brush your teeth for you using my toilet brush."
Now, knowing that I can find you and brush your teeth with my toilet brush, whether I'm truly a hacker or not doesn't matter, but you just might start brushing your teeth 10 times a day.
Bad example really, but it makes the point.
People have always used gods to explain what they don't know. You know, Rain Gods, Sun Gods, etc.
In our progress, we've eliminated a lot of questions. We understand how rain and sun work. We do not need to pray to a rain god to know when it will rain again.
What we don't know, and probably will not, is where we come from, where we're going, and why?
Polytheistic Gods have done well to step up to the plate and answer these 3 remaining questions (yes, there's more) with "You come from dirt, you'll return to dirt, and because I say so."
In this sense, it makes people think they have some purpose to fufill. A person who believes he/she is doing gods work, may perhaps do amazing things during his/her life. If these amazing things benifit others, then regardless if a God actually does exist, the mere mental thoughts inspired by the assumption that that god does exist can affect things.
However, while the assumption that a god exists can cause good for people, it also causes bad. 9/11, for instance, was a person who used religous text to his advantage to brainwash people who unquestionally believed in Allah.
I mean, try to think about being a person on a death mission. You know your about to die. How could you possibly do it, unless you were promised great rewards for your efforts?
In short, its all a mind game, and if anything, we collectivly are god. We influence gods power, hell, control it really. We carry out gods will, and we believe it is true.
And yes, people rely on religion as a crutch. There are people who at a young age were hooked on crack or something. They hit rock bottom, started questioning Why, found a bible and got some answers.
I truly believe this was the main purpose of the bible. Not so much to preach fire and brimstone, but more so to give us something to hold onto when we have no where else to turn. A place for advice on how to live/continue living.