It seems like a good technology.
N fertilisers like Urea are in shorter supply since the war in Ukraine, another factors like international shipping since covid.
This probably isn't going to change in the long term, it may relax, but demand on Gas and N fertilisers will only increase.
The invasive species tag is a consideration, but weeds are often a response to disrupted or modified environmental conditions.
Waterways are often subject to nutrient runoff pollution and changed flow conditions, weeds can be a symptom of the problems, not the real cause.
It should be possible to grow Azolla away from waterways, and also exclude wild birds that may move it to other waterways.
Azolla is a native plant to Australia.
I didn't know it was edible, and consumed by Aborigines of Australia.
https://fairdinkumseeds.com/products-page/aquatic-swamp-and-moisture-lovers/water-fern-azolla-pinnata-culture/