External data is necessary
Many companies today are data-driven but they don't have all the data they want (or need) to run the business internally. They often need to get data from external sources and combine it with their internal data to have the full picture.
One category of company that seems especially likely to purchase external data and consultant services associated with it is 104.10 Business Models - B2B2C. These companies have an indirect sales model and lack data about end customers because they're not in touch with them directly. They promote to one group of people but sell to another. Then those two groups interact with each other to actually consume the product. These companies buy a lot of consulting services in order to get the data they need to improve the business.