Inexpensive, food grade, easy to use and it works. If you're looking to use it for sopping up bacteria, metals, radiation etc in and around the mouth, swishing is fine. For general detox of radiation it's best to swallow it. I mix it into lemonade for my kids.
But beware, you have to force LOTS of water down all day or you can get constipated fast - especially if you're doing it more than once or twice a week.