The actual TOAL figures were not mentioned nor did I ask specifically those numbers when I approached and discussed with members of the B777 community I know to gain topical background.
Obviously strategic airlift.
The first B777 is currently under going P2F freighter conversion with Israel Aerospace Industries. This aircraft is ex Emirates and is a year younger than the Air NZ aircraft. The conversion has an estimated cost of USD$35m and yes it is an extensive job. Why, this hasn't happened before now is because of three main reasons. Firstly, the B777 has been so valuable, especially the 772-ER, 777-LR and the 773's in the long haul passenger market for airlines, that their used prices held up so well with many original purchasers opting to keep them in service longer. Secondly, because of that demand value of the aircraft has been high it is only now that it has become commercially justifiable commit to the higher cost to undertake the conversion. With the used value of the B777 dramatically dropping over the short term, it is now viable for the major conversion firms like GECAS/IAI to convert and on sell P2F variants into the second life air freighter market. Thirdly, the feedstock for other widebody P2F conversions such as the A300, A310, B767, and MD-11 are becoming more scare as they get older. That is why the B777 like the A330 have now begun their careers as feedstock for P2F conversions. Of the wider B777 variants, it is really only the original 772 standard that lacks the broader conversion appeal of the ER, LR and 73.
Of course even a non converted B777-200ER can carry both the full pax capacity of the B757 as well as all it can airlift with tonnes more to boot twice as far.