Upanishads are the most significant scriptures in the philosophy of Sanatana Dharma. They constitute the essence of Vedas and also known as Vedanta. We know that there are many Upanishads but 108 are recognized in Muktika Upanishad. Among them, 11 Upanishads are considered the Mukhya (principal) Upanishads on which Adi Shankaracharya has written Bhashya (commentary).
Now, among Mukhya Upanishads, I found that Mandukya Upanishad is considered to be most important. According to Muktika Upanishad:
इयं कैवल्यमुक्तिस्तु केनोपायेन सिद्ध्यति ।
माण्डूक्यमेकमेवालं मुमुक्षूणां विमुक्तये ॥ २६॥
I-i-26-29. But by what means is the Kaivalya kind of Moksha got? The Mandukya is enough.
Gaudapadacharya, the grandguru of Adi Shankaracharya has written a work on this Mandukya Upanishad, called Gaudapada Karika or Mandukya Karika which is the most important and ancient philosophical work in Advaita Vedanta, establishing the doctrine of Ajatavada.
As Muktika upanishad says Mandukya is enough for kaivalya, I want to know what makes Mandukya Upanishad so important or why it is considered most important among Upanishads? Acharya's work explaining this would be useful.