My original point was that studies suggest that maybe water treatment, of any sort, actually isn't needed in lots of environments.

I'd say that AT through hikers within 200 miles of NYC region, for example, might reasonaably want something. This is where I've done the majority of my hiking over many years. I've only treated water for past few years, due to a certain fussiness, maybe it's creeping old age.

In Cascades and Olypics, where I've also done a lot, I eschew treatment, while exercising some caution about particular sources.