From the perspective of Chapter 11, why is having a Guru in a physical form considered essential for a devotee's spiritual journey?

Chapter 11 posits that as long as a worshipper has a physical form or body, having a Guru who is also in a physical form is essential. This is because devotion cannot truly manifest without meditating on a manifest (Saguna) form. The text explains that this form provides a tangible focus for worship; it is a form at whose feet one can place their head, with whom one can exchange words of love, and who can be worshipped with offerings like sandalwood. As described in Chapter 11, this devotion to the Saguna form is what allows the 'bud of the mind' to open. It is considered the easier path, which, when followed with firm love, ultimately leads the devotee to the more abstract realization of the Nirguna or formless Brahman.