Silk is one of the popular fabrics for apparel because of its unique properties.
Silk is most luxurious fabric, the most comfortable fabric, the most absorbent of fabrics (equal to wool), the best fabric for drape, the best fabric for color, capable of the greatest luxury, having the finest "hand" etc.
These are some of the factors which make the fabric more popular.
The fabric is cool in summer and warm in winter.