According to Chapter 11 of the Sai Satcharitra, why is it important for a devotee to worship a Guru in a physical, manifest (Saguna) form?

Chapter 11 explains that for a worshipper who has a physical body, the Guru must also be in a physical form to facilitate devotion. The text emphasizes that devotion is difficult to cultivate without meditating on a manifest (Saguna) form. As this chapter states, understanding the Saguna is much easier than the Nirguna (unmanifest), and once love for the Saguna is established, the realization of the formless will follow. A physical form allows for tangible acts of worship, like placing one's head at the Guru's feet and exchanging words of love, which helps the devotee's mind to open and blossom.