Why is the Missal of 1962 important?
"The traditional liturgy in fact gives acute expression to the Sacrifice of the Cross made present on the altar, orients the soul toward God, and witnesses our adoration of His Real Presence."
(From, "The Liturgy of 1962").
I have tried, in my own dumb way, to answer this question, but I think the answer given by The Priestly Fraternity of St. Petter (FSSP) in their short note, "The Liturgy of 1962" is far better. It certainly carries more authority.