Short answers, pulled from the story.
Prostration serves to show reverence to the Triple Gem and purify defilements, especially conceit. It functions as a preparatory act for meditation sessions that follow and accumulates merit within the karmic journey.
Theravada Buddhists execute five-point veneration by placing two palms and elbows on the floor alongside two sets of toes and knees. They place their forehead directly against the ground during the motion while reciting specific prayers like Okāsa or Pali verses honoring the Buddha, Dhamma, and Sangha.
Zen master Huang Po of the 9th century wore a permanent red mark on his forehead due to doing prostrations so intensely over decades. This physical evidence suggests rigorous daily discipline required for deep practice in Zen traditions.
Vajrayana prostrations are often done three times, seven times, twenty-one times, or one hundred eight times. Large numbers like one hundred thousand prostrations become part of preliminary practices called ngöndro.
Robert Aitken stated that ritual helps to deepen religious spirit and extend its vigor to lives. Ritual also serves as an opening for the experience of forgetting the self when words or actions become one with the practitioner.