You really should offer books of some kind. I have two different ones I offer, a coffee table album (which I have made at whcc) with a custom cover and the hinged lay flat pages and a wedding style leather bound book. I sell a lot more of the coffee table styles. Though, I occasionally do sell a leather bound one, usually to my equine clients. There is a definite price difference.
They take me a lot of time as I do not use lumapix or any other software to lay them out. I do have different elements for building them though.
Clients book sessions for different reasons. I would say I am 50/50 on studio and environmental. People are very specific about which they prefer