Right? But it is part of it. It was the only part of it for centuries until later Popes realized that it was too simple and easy and decided to add some more conditions. But it is still supposedly Mary's plan of salvation of which wearing the scapular is a part --
"The Sabbatine Privilege thus consists essentially in the early liberation from purgatory, through the special intercession and petition of Mary, which she graciously exercises in favour of her devoted servants preferentially -- as we may assume -- on the day consecrated to her, Saturday. Furthermore, the conditions for the gaining of the privilege are of such a kind as justify a special trust in the assistance of Mary. It is especially required of all who wish to share in the privilege that they faithfully preserve their chastity, and recite devoutly each day the Little Hours of the Blessed Virgin. However, all those who are bound to read their Breviary, fulfil the obligation of reciting the Little Hours by reading their Office. Persons who cannot read must (instead of reciting the Little Hours) observe all the fasts prescribed by the Church as they are kept in their home diocese or place of residence, and must in addition abstain from flesh meat on all Wednesdays and Saturdays of the year, except when Christmas falls on one of these days. The obligation to read the Little Hours and to abstain from flesh meat on Wednesday and Saturday may on important grounds be changed for other pious works; the faculty to sanction this change was granted to all confessors by Leo XIII in the Decree of the Congregation of Indulgences of 11 (14) June, 1901."