I used to believe that as well. I thought that belief in God was only advantageous for weak minded individuals that couldn't make it 'on their own'. I personally didn't feel that I needed that crutch, so I couldn't see the value of it.
What I didn't realize until much later was this: If people can lean on something, that does not somehow diminish it's credibility. (Clearly, it doesn't prove it either.) The important factor is whether that support will ultimately let them down. Is it based on solid fact or flimsy fantasy?