This is also often referred to as business use case and should describe an IT need from a business perspective. Many organizations have such cases, but some lack of translating them into IT needs. Sometimes, there is simply no communication between the lines of business and the IT. This often ends in a bad relationship between those two departments. Often the business thinks IT is too slow, complex and ancient to understand their needs and deliver what they ask for. On the other hand, the IT often gets just a fraction of the problem, but then it has already escalated a few times and now only complaints reach the IT department.
Since a successful SDDC is about communication (people, processes, technology) it is important to understand the business needs of an organization to create a solution which is capable of supporting them and even give them an advantage over the competition. The first step of creating your SDDC design is to document and question that business need...