Dharma texts, as the representation of Buddha, are highly respected objects of veneration. As it states in the Avatamsaka Sutra:
In the last five hundred year period, I will appear in the form of scriptures. Consider them as identical to me, And treat them with due respect.
Just like we ourselves wish for soft clothes against their skin, warm layers to protect us from the cold, and something attractive to wear over them, our pecha covers provide a soft interior for delicate texts, a sturdy wooden backing to prevent bending, and a high quality Banares silk exterior.