The main difference is that these SaraSets are not linked to any script; you simply select a QuarkXPress file and apply a set of Saras to it, for a given range of pages.
For Standalone Saras
This can be useful:
•To apply Saras to an already generated script output file.
•To apply Saras to GridTemplates (why not) when a massive change is necessary (such as changing the default font, etc...).
The main advantage of stand-alone Saras is that they do not require you to run a script and can be applied to any valid QuarkXPress file, even files that were not generated by Q++Studio.