The caveat of finding "better" methods is that it excuses continuing or expanding the things we do that are the core problems of rapid growth, consumption, and a throwaway society. And like you said, they have their own issues that might become problematic with growth in that process. Not to say that we shouldn't try to improve what we can, just a point that being better than the worst way to do things isn't all that great either.

The word "sustainable" in the title is one of those greenwashing terms to sell a product and keep the status quo of business as usual. As the report shows.

And I guess not all of the plant is something that can be burned as fuel so done right it should be a net negative

but we have an oxygen atmosphere not a chlorine one, so it’s gonna be oxygen.

Could also be fluorine but there are other good reasons not to use anything involving that as a fuel

“It is, of course, extremely toxic, but that’s the least of the problem. It is hypergolic with every known fuel, and so rapidly hypergolic that no ignition delay has ever been measured. It is also hypergolic with such things as cloth, wood, and test engineers, not to mention asbestos, sand, and water-with which it reacts explosively. It can be kept in some of the ordinary structural metals-steel, copper, aluminium, etc.-because of the formation of a thin film of insoluble metal fluoride which protects the bulk of the metal, just as the invisible coat of oxide on aluminium keeps it from burning up in the atmosphere. If, however, this coat is melted or scrubbed off, and has no chance to reform, the operator is confronted with the problem of coping with a metal-fluorine fire. For dealing with this situation, I have always recommended a good pair of running shoes.” ― John Drury Clark, Ignition!: An informal history of liquid rocket propellants

I think that bit was about Chlorine Trifluoride but I might be misremembering.