Possible Clues:

• Help or benefit
• A bottle with contents switched is to be of use
• Benefit from a face covering, we're told
• To no __ (futile)
• A bridal accessory said to provide help
• To no ___ (without effect)
• Independent of, say, granny's housing benefit
• A curtain said to be useful
• To no — (in vain)
• Be of service to, benefit