Power BI Desktop is a robust resource for data analysis and reporting. It performs all reports, modelling using external tools such as R, Python, Querying and modelling. The Power BI service is a cloud-based service. It supports light report editing and collaboration for teams and organizations. You can connect to data sources in the Power BI service, too, but modeling is limited.
A few differences -
- Power Bi is deployed in your system whereas service is deployed on the cloud.
- Data sharing and collaboration is available in service and not in Desktop.
- Power Bi service contains more settings and features for sharing, gateway, etc.