What does the story of Narayanrao's friend and the incense ash reveal about the nature of Udi and the power of devotion?

The story from Chapter 33 powerfully illustrates that the effectiveness of Udi is deeply connected to faith. When Narayanrao's friend was stung by a scorpion and no actual Udi could be found, Narayanrao used simple ash from burnt incense sticks found under Baba's picture. He considered it as Udi and applied it with prayer. The text states, 'This was only the Vibhuti of incense sticks... But being considered as Udi from the path, such was the experience manifested.' This shows that while Udi is supremely auspicious, the devotee's unwavering faith can invoke Sai's grace and make even a substitute substance potent.