You need the destination to have a suitable container port, and a way of emptying a large number of containers into the water system quickly. If you want to use normal shipping it would probably be eaiser to just import and distribute bottled water.

A big bag would just need a pipeline to come ashore and could be more easily pumped than hundreds of shpping containers. Although the details of their plan seem sparse. Does the bag offload into a water mains system, and will it need treatment before use?