It is story line continuity. Sharmell has been the focus of this thing almost from the start. Atleast since Final Resolution. I bet if they just forgot about her, people would be nitpicking about how TNA starts things and doesnt finish them. Atleast there finishing that part of the angle. And admit, her return at Destination X was entertaining as hell. If you guys even watched the show, you may have saw it. Or maybe it sucked and the crowd only erupted for it because they were all given hits of ecstasy as they filed into the building.
The girls will stand on the ring apron, do the cat fight spot when needed, tag back out to the men, let them get to the finish, have one more squirmish, probably where Roode gets hit in the nuts from behind by Sharmell, and then Booker T finishes him with the axe kick. They celebrate, yada yada. Later in the show Robert Roode hits Booker T with his rental car and drives off.