I am allergic to anything too good to be true and, frankly, a travel guide as an “essential component” of the initial decision smells like a marketing stunt.
What really changes are the cash flows and plane tickets: most people already have an idea of their destination before opening a guide.
This guide is used to refine details, find a hotel or restaurant, not to decide whether to go to Iceland or Italy.
For example, for a trip to Germany, you don't pick a guide to decide if you're going to Germany, but where exactly and how once there.