Why is Shirdi considered a supreme pilgrimage site for Sai Baba's devotees, according to the teachings?

According to Chapter 4, Shirdi is considered the ultimate pilgrimage destination because it is believed to encompass the sanctity of all other major holy sites. For devotees, Shirdi is their Pandharpur, Jagannath, Dwarka, Gaya, Kashi, and Rameshwar all in one. The text explains that association with Sai in Shirdi provides a complete and easy spiritual path, rendering journeys to other locations unnecessary. The mere sight (Darshan) of Samarth Sai was considered a form of yoga, conversing with Him washed away sins, and partaking of His Udi-Prasad was seen as holy and sanctifying, solidifying Shirdi's status as the supreme spiritual center for His followers.