Well many parts of the world have little to no AVGAS. In Indonesia 99% of the country has no AVGAS and huge survey going on, they use Porters and Caravans.
I quoted a French company once for the use of our 206, they send planes all over the world.
Honestly I don`t think they care much about burning a bit more, some of those govt contracts are $$$$$$, for our 206 they were gonna pay 600 USDs/hour dry plus 200USDs a day for the pilot, I guess they could have done it in a caravan for that money.
Most of the survey I have seen in Europe is done on twin turbines, especially the one at at sea.
yeah maybe to buzz over NYC it`s a waste.