I think coins for entertainment are particularly useful, because if people know from the outset that they are playing with a person to person equivalent of EVE-Online currency, for the purpose of attacking it and its users in all the ways one can in EVE-Online, they maybe would not cry so hard when one of the attacks happens to lose them some of their coins. Or at least even if they did cry just as hard the media would realise hey these people lose some game currency in a game, whoop dee doo, guess what game it was folks.
Best types of game to start with would have been anarcho-capitalism games like EVE and Organised Crime turf war games.
Headlines! Crime Family in person to person distributed online game loses ten million omertacoin in virtual shootout!
Heck most players nowadays are such pathetic wimps it would also have to admit "the capos killed lost not only their cash but three points of strength and one of long-rifle accuracy, when interviewed they said "next time the other guy will be the one short some attribute points!" instead of "the players of the slain capos lost an average of ten thousand robot-hours each: the average number of robot-hours invested in developing the permanently-dead capos."