I use these as teaching aids as an orchestra teacher. We call these "bow belts." One of the best things for keeping everybody's thumbs free as they learn a beautiful bow hold. "The thumb is the tongue of the hand" - Margaret Rowell 20th century cello pedagogue.
I needed something to neaten up my flower beds after the daffodils had stopped blooming. Garden ties are too hard to use unless you have extra hands; the heavy duty rubber bands allowed me to bunch up the daffodil greenery and hold it together until it dies out. Worked great!!!