If you implement a dataset that uses a dataflow as datasource and they are in differente workspaces, lineage will show all dependecies between them only if you set lineage view from dataset >> dataflow. If you set lineage view from dataflow, it will not show the datasets that denpends on this dataflow if dataset is in different workspace.
My idea is no matter if dataset/dataflow are at the same or at different workspaces, lineage would show all dependencies.
If you follow Power BI best practices for Workspace, Dataflow and Dataset you will end up having datasets allocated in different workspace as its dataflow source. In this situation it is important to know which are the datasets that use some specific dataflow as datasource, specially to manage update schedule, access permissions.