Waist beads are worn for several reasons.
1. To beautify the body : Waist beads are beautiful aesthetically pleasing accessories worn to enhance your beauty. This is the same reason why people wear make-up, necklaces, earrings, bracelets, trendy outfits and others for aesthetic purposes. 
2. Weight Monitoring : The non-elastic clasps waist beads and the tie ons can be used to monitor your weight. The beads get tighter when you add weight, and it gets loosed when you shed some weight. Waist beads when worn, can also help you control your food intake. It serves as a way of gauging food portions. Your waist beads become tighter when you are over fed, which makes it a necessary tool to monitor food intake.
3. It Promotes Body Positivity, Self Confidence and Self-Awareness : Body positivity in simple terms mean “Loving your body regardless of how it looks”. Waist beads are non-discriminatory accessories suitable for all body sizes, shapes and complexion. Wearing them helps to boost ones self confidence, thus promoting self love, which is synonymous to body positivity. Waist beads make you feel good about yourself. They can make one just stare at the mirror in admiration. So at that point, you see the beauty in yourself, not your insecurities.
4. Spice Up Ones Sex Life : Waist beads can also be used to spice up ones sex life. Waist beads being a turn on for a whole lot of people is an open secret. They make you look more attractive and sexy when the clothes go off. The beads can also be used to “play” during fore play. 
5. Healing & Spiritual Purposes : It is believed that waist beads made of healing crystals perform specific metaphysical functions. Healing crystals such Amethyst, Rose Quartz, Tiger Eye, Black Obsidian, Carnelian, Lapis Lazuli, Clear Quartz, Green Aventurine, Citrine, Dalmatian Jasper and many others too numerous to mention, perform one healing function or the other. 
6. Cultural Reasons : To some, wearing waist beads are a thing of culture.
People wear waist beads for at least one of the reasons mentioned above.