"Only if you have no other option, narses."
Not true. Reread the letter. It is a matter of personal devotion and piety only.
Picking and choosing. As I said, I would attend an SSPX Mass, no matter how much I dreaded it, if I had no other option.
2. The Masses they celebrate are also valid, but it is considered morally illicit for the faithful to participate in these Masses unless they are physically or morally impeded from participating in a Mass celebrated by a Catholic priest in good standing (cf. Code of Canon Law, canon 844.2). The fact of not being able to assist at the celebration of the so-called "Tridentine" Mass is not considered a sufficient motive for attending such Masses.3. While it is true that the participation in the Mass and sacraments at the chapels of the Society of St. Pius X does not of itself consititute "formal adherence to the schism", such adherence can come about over a period of time as one slowly imbibes a mentality which separates itself from the magisterium of the Supreme Pontiff. Father Peter R. Scott, District Superior of the Society in the United States, has publicaly stated that he deplores the "liberalism" of "those who refuse to condemn the New Mass as absolutely offensive to God, or the religious liberty and ecumenism of the postconcilliar church." With such an attitude the society of St. Pius X is effectively tending to establish its own canons of orthodoxy and hence to separate itself from the magisterium of the Supreme Pontiff. (Commission Ecclesia Dei, Protocol 117/95)