I bought Jehovah's Witness themed cards, diaries, notebook, pens and magazine holders plus a very expensive leather cover for my reference bible from a company on the internet.
Most in my cong used them especially the combo pen/highlighter with the years text on it and the diary as it had the ministry school and service meeting schedule in it and a field service notes section too.
I am surprised the society didn't make them and sell these kind of items themselves or close him down. I don't see that an app is any different.