There are many ways to use the sun to desalinate that seem more appropriate to getting drinking water to humans in poor parts of the world.
For example, this is another MIT project: https://news.mit.edu/2022/solar-desalination-system-inexpens...
The interesting part about this is probably that even the prototype is fairly compact and weighs like 10kg and that they claim to be able to achieve that with brackish water. If they can prove that it’s as robust as claimed, that sounds like an interesting technology.
But that's what most hackathons are in reality anyways.
However, their envisioned use case is not “helicopterdump across the desert” but very specific use cases, often for people with technical skills:
> This could enable the unit to be deployed in remote and severely resource-limited areas, such as communities on small islands or aboard seafaring cargo ships. It could also be used to aid refugees fleeing natural disasters or by soldiers carrying out long-term military operations.
Whether they succeed in making a device useful these cases is a good question, but I consider it pretty dismissive that you characterize a 10 year research effort as “most hackathons”
(1) https://news.ycombinator.com/item?id=31200793, also linked in the article for this post.