@jamiroquai I’ve tried them and can say they work fine! I’ve had mine for nearly a year now (received it for Christmas last year) and have no complaints. I add a few drops of essential oils to it before each load and it adds a fresh scent. It’s also far less harmful than the artificial fragrances on dryer sheets and I would say cheaper in the long run as I haven’t had to replace it.
It's also important to consider than dryer sheets are primarily made out of polyester, which is a synthetic material. Having this tumble around with your clothes transfers micro-plastics onto them. Those micro-plastics are then transferred onto your skin. Dryer balls are (usually) 100% cotton and less harmful to the environment and your health.