(As an atheist who found The God Delusion to be one of the most important books I've ever read, as it gave me a solid framework of arguing in what I already considered to be true)
It's okay to read more digestible books, and not serious academic studies. In fact it's more than okay -- in order to understand an academic study you likely need to do a lot of reading on the topic before hand. A pop sci/culture book is very self contained. I can assure you that very few people in the world can read The Genealogy of Morals and understand much of it without having read a significant amount of philosophy before.
Personally, I read Thus Spoke Zarathustra before reading The God Delusion. I can't remember much of the Nietzsche book, but The God Delusion's arguments are forever etched into my brain. It doesn't matter if I didn't get the Russell's teapot argument from a primary source, it matters that I got it.