Workspaces are isolated by default: content and screens in one are invisible from another. That isolation is the point, and it is why a shared playlist is the single exception to it.
What crosses the boundary
A playlist, and only in one direction. The receiving workspace can put it on their screens and decide where it plays. They cannot change what is in it, and the content stays hosted by the workspace that shared it.
So one team keeps control of the material while another decides where it appears. Update it once and every workspace showing it follows.
That fits brand-controlled content across regions, a central team feeding local teams, or an agency running screens for a client.
What does not cross
Screens, content, labels, and members are all workspace-local. A label in one workspace means nothing in another, and there is no cross-workspace search.
If two teams both need to edit the same thing, they want one workspace, or linked workspaces if the reason for splitting them is billing rather than access.
Doing it
Sharing is a playlist action and needs Admin or Owner rights in both workspaces. See Share with another workspace.
Shared playlists are an Enterprise feature.