Water purification tablets are either chlorine (most common) or iodine based. So essentially this is the equivalent of a chlorine based tablet plus some flocculent to cause sediment to settle out of the water.

A lifestraw is better at removing bacteria, viruses, and protozoa. See page 7 here. https://www.who.int/water_sanitation_health/publications/hwt...

I don't know the cost of lifestraws to NGOs, but I guess they're more expensive. And you need one lifestraw per person, where these sachets can do bulk buckets of water.

Well, for one you get 10 l of water at a time. For another, most water purification tablets taste horrible, and don't do anything about sediment.