This product was developed by Proctor & Gamble as an affordable water treatment for the third world. IIRC it was shown to reduce the incidence of waterborne diseases in field trials in places like Guatemala. The unit cost was really low, something like twenty cents per packet.
Where it differs from typical backpacker water treatments is the flocculant to settle out suspended particles and therefore, a lot of the bacteria load. Were I could easily see it adopted would be for float trips on silty/muddy rivers. For backpacking it might be a solution for larger parties but with the understanding that it's not for treatment on the go, due to the settling and decanting times. Again, it's targeted at cloudy water sources.
I do not know whether the powder can be divided up to dose smaller amounts of water.