Attribution aside, I'd like to see the technique more widely known and practiced. The commenter was defending fish farming by favorably comparing it to cows, but ignored shellfish polycultures probably because they simply didn't know about them.
It appears to be mainly China that practices it widely. To the extent the Chinese aren't scaling it globally as a climate-friendly alternative to fish farming, they leave an opportunity for other players.
Some links:
http://www.circleofblue.org/2012/china/chinas-marine-aquacul...
https://en.wikipedia.org/wiki/Aquaculture_in_China
https://theconversation.com/how-farming-giant-seaweed-can-fe... (discusses both GreenWave and China)
And to come back to the topic of the original post: there's an invasive species of Japanese oysters in the Dutch Wadden Sea that you're free to harvest if you're in the neighbourhood. Although the debate on whether they are an ecological disaster or help restore the environment is not set, it's probably going to be the former if left unchecked, so you'll probably be helping out in the process.