Because of its opening verse:
This is the only path for the purification of beings, for the overcoming of sorrow and lamentation, for the disappearance of pain and distress, for the attainment of the right method, and for the realization of Unbinding,
Maha-satipatthana Sutta is usually regarded as the most important guideline for Buddhist Soteriology. Many meditative practices, such as Vipassana, Zen, and Anapana, are based on this sutta.
Satipatthāna refers to the broad conception of Buddhist meditation in the Theravada Buddhist tradition. It is often called the Four Foundations of Mindfulness, namely, mindfulness of the body, of thoughts or the mind, of feelings and of mental objects or qualities. These are also known as the "four frames of reference" or Satipatthāna-samyutta. Satipatthāna can also be thought of as "establishing mindfulness" or sati-upatthāna.
Maha-satipatthana Sutta has become the foundation of the Vipassana Tradition in Theravada Buddhism. Vipassana, or Insight Meditation, puts emphasis on mindfulness (sati). The principles are also practiced in most traditions of Buddhism which emphasize meditation such as the Zen or Soto Zen tradition.
Satipatthāna is thought of as a way of implementing the right mindfulness and, less directly, the right concentration parts of the Noble Eightfold Path. Satipatthāna meditation goes hand-in-hand with vipassana, samatha or calming meditation, and anapana meditation.