Having in the past been part of a church-going group, I think what has been said so far is correct. People get a sense of, albeit false, comfort from it. Their is also strong family and social connections with going to church that can be difficult to break. I kept going for a long time even though I had lost "the faith" long before.
What makes me particularily angry are those who insist on foisting their "Christian brand" of religion on me by insisting on mixing politics with personal faith beliefs.