To reuse an imported dataset, there are three options I’m aware of:
Report in the Power BI Service. This refers to using the web interface for creating a new report separate from the original PBIX file.
Analyze In Excel. This refers to creating an Excel report and can currently be used by anyone with read or edit access to the dataset. Hence, very useful for self-service BI purposes.
Power BI Service Live Connection. This refers to creating a Power BI Desktop report. This option can currently only be used by people with edit permissions on the dataset (so not appropriate for broad self-service BI reporting at this time).
Click through for a detailed demonstration of each.