According to Chapter 11, why is it important for a devotee to worship a Guru in a physical form?

Chapter 11 emphasizes the importance of a Guru in a physical form for a devotee who also has a physical body. The scripture determines that for the formless, the formless is suitable, but as long as the worshipper has a form, the Guru must also be in a physical form. The text argues that a physical form is necessary for practical devotion, as it is something that can be seen with the eyes, whose feet the head can be placed upon, and with whom words of love can be exchanged. As explained in this chapter, devotion to the manifest (Saguna) form is what allows the bud of the mind to open.