Why use "Run as Shell"

I am sorry but I can not find any documentation on advantages/disadvantages or why/why not to use "Run as Shell" in the Multi Application Edition - User Guide.

"Run as Shell" completely removes the Windows Desktop from running. Some programs (ie: Secure Lockdown Master Applications) need the Desktop underlying functionality (ie volume control, taskbar, etc), but most don’t need it. Not using it is preferred because the OS will requires less resources and can eliminate some potential trouble areas when locked down. Windows Embedded environments do not use the Windows Desktop - "Run as Shell" creates a similar environment. Some programs may be to access undesired functions of the Windows Desktop... This is a somewhat vague answer, but the Windows Desktop provides a lot of functionality that may or may not be desired in a locked-down environment. The basic rule-of-thumb is to use "Run as Shell" if no features of your Master Application require it (typically a trial and error process to discover if the Desktop is needed).