Heyo,

To be more specific, the random GNW has to do if someone does not participate in GNW player wise or if your group was disqualified. In that case, you can join this additional GNW mode. The person with the highest power in there, is the commander basically. Also, if I remember correctly if the field wins, the commander is getting 30% more rewards than the other players on the field. However, if the field loses, the commander gets 20% less rewards than the other members.