What are themes in Power BI used for?

Themes in Power BI are primarily used to apply consistent color schemes and styles across reports. When a theme is applied, it allows users to maintain a uniform appearance throughout visualization elements, such as charts, tables, and backgrounds. This consistency in design not only enhances the aesthetic appeal of the reports but also improves user comprehension by ensuring that similar data points or categories are color-coded in an easily recognizable way.

By utilizing themes, report creators can quickly establish a visual identity that aligns with organizational branding or presentation standards, allowing for a more professional look in report presentations. Users can create custom themes or select from predefined themes to ensure that all report elements are harmonized.

The other options do not accurately describe the purpose of themes in Power BI. Controlling user access relates to security features, scheduling dataset refresh pertains to data management operations, and configuring data relationships concerns the structuring of data within the modeling phase. Each of these functions serves distinct roles that are separate from the visual design aspects covered by themes.