Regardless, these cards allowing everyone to profit makes them a bit ambiguous in power level
But hear me out
If more than one player is instructed to mill at the same time (by the activated ability of Raul, Trouble Shooter, for example), as long as at least one nonland card is milled, The Wise Mothman's last ability will trigger just once
If there are other benefits as well, they will be mentioned
Of course, the Un-sets are non-canon so this probably didn't happen, but there's nothing to say that Volrath doesn't actually own a refrigerator in his nightmare plane of Rath and he booby-trapped his favourite food
I'll go on about the Mega Hyper Rare in a moment, but the rest of Phantasmal Flames' crop of IRs, SIRs, and URs are more than good enough to make this set worth buying