It's useful for removing defects and for general photo retouching. The Healing Brush Tool paints samples from one part of an image onto another. To use a document containing multiple layers and/or vector objects, you must flatten the document first. The Global source can only be defined from a single, pixel layer.
Any new documents can make use of the panel's global sources. The Sources panel stores all your global sources you can then select any stored global source and clone from it. You can define a global source in a secondary open document and paint the sampled pixels into your working document by selecting the clone source option 'Global'.
The clone source can be one of the following context toolbar options: Introducing a cloned object to your image.
