It is a simplified version of how something works without technical information about it and help to make sense of it. The main purpose of a Domain Business Model is to capture Domain Expert’s mental model, their thought process and how things work. Domain Business Model is not a direct copy of a real world; it should only contain enough information to solve a particular problem.
Why Domain Business Model is important
This is an important part of Strategic Design process. it helps everyone to understand how everything works, but also to discover knowledge that is already there. It also may help you find ambiguities in the understanding of the business model (Happy paths and edge cases) which may help to discover concepts that lack of definition and need further refinement.