If you study the biography of Bill W., he was obviously a selfish, spiritually bankrupt person who inhabited a miserable, shrunken little world that revolved solely around his narrow, personal urges and needs.
For him, embracing a traditional notion of God - something bigger than himself that freed him from his unsatisfying narcissistic ways - was the answer.
To one degree or another, I think all addicts have the same problem even if we're not clinical narcissists (as Bill W appeared to be); we've all fruitlessly sought spiritual fulfillment through the high provided by our drug of choice. Like Bill W, we all end up imprisoned in shrunken worlds where the only thing that matters is vainly seeking the ever vanishing emotional and spiritual reward provided by the emotional effect of our drugs of choice.
So even for somebody like me, who can never embrace the God of Bill W and AA, I had to find a spiritual awakening to get sober. I had to escape from the shrunken prison world in which I'd confined myself and find joy and contentment in the world as it exists in sober reality.
But the world of sober reality really can be wondrous, various, beautiful, and new. Something created it. Even if that entity is indifferent to my daily needs and concerns (as it appears to be) my sobriety is dependent on embracing and relishing the joys of the world it created.
So I think you can be damn near atheist yet embrace the spiritual program at the heart of AA. And the 12 steps heavily emphasize a de-emphasis on selfish needs and urges.
If we all - addicts of not - truly took an honest moral inventory of ourselves and earnestly sought to cast aside harmful, selfish behavior imagine what a better world we'd have?
But for the addict, fulfillment through things that are not narrowly personal is utterly essential. What is a craving, after all? An intensely internal, personal (selfish) need to satisfy a harmful emotional and physical urge. If you can find a way to live a life less powerfully dictated by selfish needs, then urges will be much easier to shrug off.
So AA and it's program has been helpful for me even if I haven't embraced it with the vigor that others do, and haven't practiced the steps in the conventional manner that most AA acolytes would recommend.