According to the teachings in Chapter 11, why is having a Guru in a physical form considered essential for a devotee?

Chapter 11 emphasizes the necessity of a physical Guru for a devotee who themselves possesses a physical body. The text states that as long as the worshipper has a form, the Guru must also be in a physical form, noting this as the determination of the scriptures. This manifest form is essential because it facilitates tangible acts of devotion. For instance, as described in this chapter, a devotee can place their head at the Guru's feet, exchange words of love, and perform worship with sandalwood and grains. Without meditating on the Saguna form, true devotion cannot manifest.