Leading Manufacturer of Silk Cushions And Bedsheets, Bed Covers from Varanasi. Silk is considered to be a hypoallergenic material, because it is highly resistant to dust mites, deterioration, and is excellent at wicking away moisture-causing bacteria. In comparison, cotton bedding is the perfect place for bacteria to grow, since this type of fabric readily absorbs moisture.Bedsheets are used to cover your mattress whereas the bed covers are used to protect these sheets. ... Bedsheets are spread right at the bottom of a mattress whereas the bed cover is spread over the bedsheets. Bedsheets are laid out when your bed is in use but bed covers are used when your bed is not in use