A: Yes, thanks for pointing out that it's not clear from the feature descriptions.
You can create folders in workspaces and set up different permissions for each user group to each folder - whether they can view, edit or even delete maps in a given folder.
Btw we also improved the security of sharing individual maps - for link sharing, you can generate a new link (so the old one stops working) or you can give (and revoke) access only to specific users (view or edit).