According to a mate of mine in CX (who regularly reads this forum - g'day Grunt!) the raison de existance of the SO, is to
* hold the sandwich tray during TO and initial climb, and ensure the sammies don't get dried out by exposure to the aircon (but don't breathe on them
* agree with the brilliant plans promulgated by the Captain and occasionally FO, for their retirement / promotion
* During the captains rest periods, pre-program the next lot of freqs into the FMS; and if the FO is feeling expansive, as a special treat he may allow the SO to talk on the HF once or twice.
For this, he gets paid roughly twice what I get, plus O/Ns in plush hotels with hot and cold running FAs.
Who's the mug?