What would atheists be praying about? Who would they pray to? It is equal to saying an atheist says speaking to a box guarantees forgiveness. Most atheists believe that boxes exist, so it might do them some good.
Atheists are a lot of things, but most are not ignorant at all, some are quite educated and intelligent. That is often WHY they are atheists, because they think they don't need gods to get along in the world. Guess what? They are right about that.
I don't pray, even when I got cancer land thought I might die. I didn't have a thing to pray about. Or anything to pray to. I am fine now, thanks.