Tomaz Kastrun wants to know what you can see:
This way, you will have a better view of users, and their access to data and reports (if these are containing sensible data). You can always retrieve the list of workspaces and access the list of all users with the PowerShell cmdlet Get-PowerBIWorkspace.
I have also added the Join-Object module. It can join two objects or two arrays, based on the given matching columns.
Click through for a Powershell script which does the job.