Creating pivot tables in Excel Online can help draw conclusions from large datasets by summarizing and filtering data based on user-defined criteria. Pivot tables are particularly useful for analyzing flat data, such as expenses or project information, to gain insights into trends and patterns. The process of creating a pivot table involves selecting the relevant data, adding fields to the rows and columns, values section, and filters, and then using drag-and-drop functionality to build the desired report. By mastering pivot tables in Excel Online, users can create dynamic reports that provide actionable insights into their data, making it easier to make informed decisions and drive business growth.