Mafia sponsorship of saints functions as reputation advertising. [causal]
Folklore aside, what these "Don Peppes" are doing amounts essentially to advertising. This peculiar form of sponsorship—the sponsor is the mafioso, the saint his innocent beneficiary—relies, like all publicity, on contemporary beliefs and exploits both the general attributes of sanctity and those specific to each individual saint. In this case it signals to the world at large that Don Peppe's "protection firm" is so powerful as to offer its earthly protection even to a protector par excellence. Thus the language of Catholicism may serve to enhance the reputation of the mafia firm. But advertising must adjust itself to the people's values. In the more secular United States, John Gotti, the man who, according to the Federal Bureau of Investigation, is the "boss of bosses," organizes annually at his own expense a celebrated fireworks display. Although he does not concern himself overmuch with saints, like his Sicilian counterparts he revels in charity and good works, clear signs of a noble and honorable character, regardless of religious beliefs
Diego Gambetta, The Sicilian Mafia The Busi…, loc. 125