Based on my initial audience, it's definitely not common. The Christians I know have different levels of familiarity with the books of the Bible.
Personally, I know Genesis/Exodus, Psalms, and the Gospels well. I can recognize Epistles on sight, but identifying the exact one is really just a guessing game. Most everything else I am not familiar with and will take me a while to guess.
I think that's why people have enjoyed it so far, because of the tradeoff of getting a verse you recognize (so you can guess the book quickly) or getting an unfamiliar verse (so you get to expand your familiarity with the Bible).
Personally, I know Genesis/Exodus, Psalms, and the Gospels well. I can recognize Epistles on sight, but identifying the exact one is really just a guessing game. Most everything else I am not familiar with and will take me a while to guess.
I think that's why people have enjoyed it so far, because of the tradeoff of getting a verse you recognize (so you can guess the book quickly) or getting an unfamiliar verse (so you get to expand your familiarity with the Bible).