It wasn't because of its rarity, but because it had two unparalleled effects. First, any piece of clothing woven from Profound Celestial Silk was completely immune to all Fire Attribute Elemental Power. This meant that if one wore these shoes, they could walk through high-temperature magma or fiery zones completely unimpeded… though this only applied to the parts of the body covered by the Profound Celestial Silk.
Second, as long as one wore clothing woven from Profound Celestial Silk, the Heaven and Earth Primordial Power would constantly and autonomously flow into their body through the silk—an effect even more significant than that of the Seven-Colored Glaze. The Seven-Colored Glaze only increased one's Cultivation speed while they were actively cultivating, but this item helped one cultivate at every single moment.
