John Doe explained it as being similar to the Super Hornet's ability to switch out its gun for the ATARS - the Navy wants the option to take it out when they want to and thus having to deal with the RCS of a gun pod.
Say what? ATARS on a Super Hornet? Who told you that? John Doe? Super Hornet went route of SHARP, which is a podded EO/IR collection system. USMC went route of ATARS, which is installed in gun cavity.