The business development team is typically involved directly with deal processes, as they are responsible for prospecting and managing new business opportunities. They have first-hand insights into the workflows, challenges, and interactions that are part of the sales process. Gathering use cases from the business development team ensures that the implemented solution will address the actual needs and scenarios encountered during sales activities.
According to Salesforce's best practices, involving the business development team helps align the solution with real-world practices and provides actionable insights to build effective deal processes.