Well no one likes plastic in the ocean, but I'm a bit skeptical. They also don't go into too much detail on how they don't kill smaller fish, krill, jellys etc.
Note a 500 m aperture sweeping at 2 kts (1 m/s) over an area of (1000 km)^2 would take 63 years. Maybe they only sweep 1 kt, and only do 200m. But a few hundred of them might do some good. Then you have to actually get all the plastic back to shore and into a landfill. Or compress it at sea to solid masses heavier than water, that will not ever themselves disintegrate, and sink them?
Meanwhile the the pollution is still incoming, mostly from 10 rivers in Africa and Asia.
https://www.scientificamerican.com/a...in-the-oceans/
https://phys.org/news/2017-06-plasti...rce-ocean.html
So if there is no source control, this whole program is basically a bunch of Americans spending money to move plastic refuse from China to landfills in the western US.