One definition of mystificateur is of a hoaxer or trickster, or of a man without profession who makes an art of dining out at others expense, by value of his ability to entertain. While card and magic tricks may have been a specialization of his, as a producer of cartomancy decks one can easily suspects that card-reading may have been amongst his repertoire of parlour amusements, if the biographer's description is indeed accurate.
Le Petit Escamoteur, published as being available from the author, at Saint-Sauver's address -- is testament also to the biographer's description of JdS-S as a practioner d'escamotage. The fact that it was also combined with Deroy's Le maniere de tireur des carts, ou le cartomancien in the Pigoreau edition also that card and magic tricks were viewed as belonging together with cartomancy as 'parlour amusements' (oracles for the ladies perhaps, tricks for the men?).