Do you hear the news?

On the subject of "closet" drama (see my previous post), I'm intrigued by the fact that Cavendish, though writing for a reading audience, incorporates so many elements from the theatrical tradition (deliberate use of the the stage architecture, prose and verse alterations, even collaborative writing). One element that comes back repeatedly is the use of messenger characters to relay information from "off stage" (throughout both parts of Bell in Campo the device is used several times -- often with extremely long descriptions of the "off stage" activity; the exception seems to be, ironically, what should be the climactic reporting episode in scene 16 of part 2 but which ends up being the shortest reporting exchange in either play). This device goes back to the Greek theatre and was still in some limited use by the Restoration. My question is: given that she is writing for a reading audience and has the freedom and flexibility of playing directly upon their imaginations rather than playing upon the spatially and temporally limited space of the stage, why does she consistently use this device? Why tell about these important events through reporters and not show them actively before us?