I see what you mean shuffler, but I can imagine most reputable airlines expecting the Captain to operate the aircraft on the MEL with one pack inoperative. In fact, it is something that most Captains will probably see in their career. So, with that being the case, it would be nice to know what the cabin temp is going to be on the off chance that your one good pack lets go.
If I turn up to work tomorrow and am flight planned at FL 250 with a pack out, when we are over an hour from the nearest airport and 170 POB I would like to have an accurate idea of the consequences of the one remaining pack malfunctioning.
I agree it is not highly likely, but I don't think it's quite zombie apocalypse Hollywood stuff.