If you Google "Clearwave water softener" you'll get lots of info. The device seems to work by preventing hard water particles from precipitating, i.e. they stay in suspension. There are a couple of university test reports on one web site. The benefits seem to be the prevention of scale formation in water heaters and other water system components. It also reduces the interaction of water hardness with detergents, so you'll use less soap and detergent. However, your drinking water will still contain all the salts and other impurites that the water supply has.
There doesn't seem to be a perfect solution to getting great water. Each system will do something but not everything. You'd need filters, chlorination/UV treatment, carbon filters and a water softener to get pure water. I tend to drink whatever's on offer in a campground, and just use a carbon filter to remove that "campground taste" that occurs from time to time. I've never had a problem with scale formation, routine heater maintenance seems to take care of that.