When a collaborator is invited to a project, he or she is granted a Collaboration License. This license gives the collaborator the right to access and modify the project at hand. In addition, by joining a project as a collaborator, one grants a royalty-free license to the project creator to use any of the content contributed to that project by the collaborator. This grant provides the original creator the ability to monetize his project, which may include the collaborator's contributions, as he wishes, royalty-free.
If you want to take someone’s project on which you are a collaborator and add it to your own workspace for your own use, you must first get the permission of the original creator before doing so. Similarly, you must get the permission of the creator if you want to then take that project that you saved to your workspace and make it public.